The Early 80's

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End of day 1. 1983 Liberty XL. Back 4 hubs stripped down to the spindles.

The owner is up to his armpits in grease. He wanted to help so ive lined up an entire day , tomorrow, of cleaning and degreasing all these hubs and brake components. I wonder if he will be as excited to help next time? He saved himself a days labor thsts what it would take me to do it, 1 entire day.

Tomorrow ill pull brake chambers and hoses, airbags, rebuild the air dryer and put new ride height valves.

So far she is being a good patient.

Thank u for the refferal Mr. Boater Al

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A good days work. R there others out there that get this dirty or is it just me? Busted knuckles and greasy jeans thats me. My knees were just as dirty as my shorts, I cleaned up for the photo.

LOL Joe that is exactly what I looked like a couple weeks ago when I did my wheel seal. Joe I was wondering what is the process of rebuilding the air dryer?

So Joe - you are wanting some dirty pics. Might have better luck on some other forums??

Hey Mark, your 99 could have a couple different ones. Does it have a lid that looks like a 10 gal hat? Thats an AD9. Is it a spin on? Those r Haldex, This one is an AD 2 I know u dont have this one. Yours will be forward of the drives, drivers side. If u have no history with your 99 Id put a bran new one first then rebuild every 2 years going forward.

Billy get yer mind out of the gutter.

Ok. Here we go. Ive jotted down better than a dozen things that someone will encounter on a similar repair on early 80s. So far my list only concerns the rear, havent even peeked at the front (the notes and thought will expand when i get there) Im pretty confident it will be interesting stuff.

Im taking a long 3hr mid day brake during this one and its perfect for me to allow me to have u follow along. Should take me almost a week. If u r planing on doing similar the thread will be priceless.

Even though its 37yr old the design of the rear suspension has been unaltered right up to 2020. It has been beefed up a half dozen times here and there but the design remains the same. Thats a 40 year run!!!!!!


U will see. Im working methodicly and cant wait to get to the finish line on this 83. It will be one of my finest moments rubbin on this old girl and it should turn out to be a damn good thread too. Im sharing as much the relevent stuff as i can.

Item 1

Lets start with the air dryer.

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The AD2 (air dryer 2). Standing vertical cilindrical and center photo. All parts still available. It is very easily serviced on the bus. Remove RR tag tire and wheel to acess easier.

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Here is the base on the ground this is what u look up at. Remove the air line first then the wire going to the heating element. Then the 3 1/2 in bolts hold 3 clips (in the forground in the pic above) take them off next. After that tap on the base with a rubber mallet driving it up into the housing sufficiantly enough to get thw large snap ring out.

That will get u to the ground like the image.

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Once the base is off u expose the cartrage. u r looking up here at the base of the dryer still on the bus. A 3/4 in bolt.

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When u turn out the 3/4 in bolt and pull it out the bottom this is what they look like. Reverse the removal process to install.

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here is the purge port. If u want to rebuild this its a seporate kit.

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here is the heating element. It too is a seporate kit.

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There r 2 choices for the manner to refresh the dessicant. Like the photo or a bag of beeds and some screens and cloth filters and u can dissassemble the canister and repack the exzisting one. I prefer the alternative.

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Heres a m.i.f. (maintence induced failure) . I dont care who the hell u r when u r working on 20 year old stuff, and older, there will be m.i.f.s.

The old canister base broke off and it was like a finger was removed from the dam and i had a mess to cleann up and had to then devise a way to get the old canister pryed out of the housing. Thats ok. Theres gonna be mifs, and i always win fear not.

QUESTIONS?? If not Ill proceed to the next item.

Joe,

Great info as always!

Because you weren't in Florida and Prevost was having a sale on air dryers and parts, I spent the day at Prevost. They knocked out a couple of things before our trip west. The rest of the stuff is waiting for you.

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No sense in driving to Prevost and not walking down to 4 Rivers BBQ for lunch.

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Mmmmmmmm. That looks good. I got Campbells chicken noodle on the burner. What gave u the impression i was messin with yer stuff. Post like that aint doin u no favors U better be nice to me. I got feelings u know.

Gill set yer GPS for no tolls no freeways. Have a great time Darline dont take no crap from Gill make him do everything on command.

This is going to be a good thread buddy, i got notes.

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End of day 2. Both rear corners stripped of brakes down to the spindles and now its suspension has also been stripped from it too. Then it got a good swabbin with a power washer and a 50/50 mix of aluminum brightner and water in a pump sprayer. Shes prepped for paint. www.Por15.com This is what i would use for undercarrage. To replicate what the factory did u will need silver black and grey all 3 colors. U can shoot this stuff but I apply it with brush and roller. This is one of those amazing products. If when u reseal any unused product if u dont clean the rim of rhe can before replacing the lid........The lid gets welded it u cant open it that way. Good product!!!!!

All the spray foam on top of the wheels gets undercoating from a rattle can.

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Heres my test pilot fir the week. Got him good and greasy didnt I!!! Got another lost sheep for ya Jamie be lookin for Chad in the member requests!

Back to buisness 83 chassis restoration.

Item 2.
The maxis (emergency brake chambers) on the drives.

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Old and DANGEROUS. If u loosten this clamp where im pointing without having the main spring caged as the clamp gets to the loose enough point the 2 halves will seporate in a violent explosion. Be a good experiment for mith busters.

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ONLY remove this clamp where im pointing in this pic on the old chambers that facilitate both. This is the service diaphram and it has a spring but its week and far from deadly. The modern 30/36s r designed with only 1 removable clamp, the service diaphram clamp (the safe one).

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Here is another m.i.f. Any brass street elbows this vintage remove them for more modern streeelbows they r way more robust. It took very very little force to snap this. This line is pressurized to colapse the main spring if it snaps goin down the road this hub locks up.

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Then there r these dirt boots for the pushrods. All prevo with drum brakes drive axle had these if yours r damaged or missing thats a points deduction. U dont see these on trucks. Its one of the many things u only see on prevo. U want to have a special camper this is one of the things that contributes to that. Keep it whole. This piece has its own part number the 30 36s do not include it.

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When u buy the chambers from prevo they r a bit more and worth it.

Where im pointing in the pic above, the 2 halves always come clocked correctly, the relationship between the fittings on the side and the mounting studs on rhe end with the pushrod. Others dont clock them. 1 to the good.

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The pushrod always comes cut to the perfect length. Others dont, very important. Thats 2

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It comes with the correct clevis, others dont. 3 reasons to get them from prevo.

Up until around 94 the only axles that have an emergency brake r the drives. 2 good opperating chambers r safe. If u loose preformance on 1 of the 2 Id be real careful about setting the emergency brakes and walking away with a toad hooked on ANY SLOPE. It might hold it, it might not. If the 1 remaining hub lets say has some oiled up pads from a leaky seal u will be off to the races. Be carful take no chances with chassis that only have emergency brakes on the drives.

Item 3. 1983 Chassis Restoration

Brake Relays

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The end of 83 and the beginning of 84 thats when the width of the bus went from 96 in to a full 8ft.

Just as significant a milepost as the 99 to 2000 model year changes were when the XL Became the XLII

Many other elements changed too. The brake relays r 1 of those other things. The pre 84, 96in buses used R6 relays NOT R12. Its kind of tough to decipher from these photos especially if u dont know what your looking at but these r not r12 and r quite the oddity.

Im sure of whats here and unaltered and heres why. Another difference is the 96 wides pre 84s have ALL copper plumbing not easy to put anthing other than perfect replacements and thats what im looking at. Prevo Elgin also verifyed it was built with r6.

Prevo parts doesnt make too many mistakes but the associate verifyed no availability for an original R6 and erroniously shipped us 3 R12s telling us they would work. NOT. Not only would it require major surgery to replumb it because of the copper but more importantly the crack pressures r different r6 r12 and it would alter the dynamics and preformance. In their defence Ive never encountered an r 6 on a semi tractor, dollies and trailers, old ones maybe. Either did a good friend with a similar background OR the guy at fleetpride that has never been asked for 1 in over 20yr.

Im going to eventually talk to tech at bendex and find out what im told.

We found new old stock on ebay for 25 bucks a piece. I havent actually pulled these out yet. That will only happen when placed in my hand in a couple days. There r 2 in the back. The front one became really accessable once ive pulled the tires, and shock, and airbag, and hub, and the maxi now its a piece of cake. lol. i can reach right in there. Very nice.

It would be neglegant on my part to go this deep and leave these in there. This is a job that if a shop was asked to pull this 1 part and nothig else would be a royal pain in the ass task. The back one is entirely more accessable by pulling the base of the bed and removing the engine hatch. Chad tells me hes had it out before its not 15min of time. Ill swab and blast all that down too when I do.

The R6.......learn somethin new every chassis.

This wonderful 83 chassis.......Im the best thing thats happened to this bus since Liberty rolled it out the door 37 years ago.

Item 4

Brake Hoses

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This is a Parker Hose. It has a swivel it is 1/2 in and its a made to length 1 time use throw away. Most chassis now have these.

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Many earlier chassis all the way up to 2000 or so were endowed with Aeroquip 2 Piece swivel ends on the chamber end and a brass 2 piece non swivel on the end that screws into the relay.

This 83 came with a full set over the years it has been stripped of 3 of them for the lessor brand. Either someone took them and reused them or worse yet they ended up in the garbage. That aeroquip 1/2 by1/2 swivel with adaptor is 70 or 75 bucks. The other brass end is more reasonable.

These r great hose ends they r forever unless u destroy it trying to remove and disassemble it.

If your chassis has these dont let some scoostama remove them. For 5 or 6 dollars for the hose and 2 bucks for the brass ring and a few minuites it is totally rebuildable. With a few feet of spare and a couple compression rings u can redo a damaged hose yourself or at lease have the right stuff when the road service shows up.

Most All the air hose on the bus Is plastic or in the case of this 83 brass. This always takes preferance. Its stronger and lasts longer than rubber.

However if u have movement between the 2 ends of a line plastic will crack it has to be rubber in these spots.

Well there is a TOTAL of 8 rubber hoses on the chassis in 84 and 2020 remains the same 8.

This is the logic behind the design.

When its time to replace the rubber brake hose the throw away parker hose can for rhe same money be replaced with the reusable ends, the brass 2 piece on both ends. Going forward to the next decade and next replacement the cost is reduced significantly.

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Theres 6 rubber hoses on the back and 2 up front for everybody. Heres the maxi waiting with all its drive hub related buddies waiting to team back up.

New, return springs, new rollers, new inner seal and gasket, new axle wedges, new tapered brake drum screws and complete drain of drive axle for 5 fresh gal synthetic oil.

The wheel bearings and races were all very good. The S cam seals and bushings were quite free while showing very little play all the alack adjusters were fine. All 37yr old stuff and still functioning as designed. Thats good juju to let these pieces roll.

Joe, you're a busy guy. I'll buy you lunch :-)

BTW, I heard Prevost Parts has a dded a few bucks in their marketing budget for you to promote their parts. Was that a good rumor ;-)

Keep up the good work!

R U makin smoke?? Where r u? The forum always gets quiet just prior a rally. I sence lot a people movin around. Yall be carful and have fun. I need another couple years before my Pete is finished enough to bring out in public. Then we will run up some miles togeather.

I want to go find some UFOs that be a fun trip.

Item 5

Shocks and Shock Posts

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All this hardware stuff on pre 84 r different. Same shocks but installation different. First the suds r bolts that go all the way thru the suspension carrage. They also have 2 opposing wedges . Another item is the bolts need collers to go into the shock eyelets. The collers serve a duel purpose and facilitate bottoming out the nut when u run them up. If the long bolts r allowed to loosen up any the wedges start grinding on the tapered seat and if u wollow out those seats thats going to create a lot of time getting straight again.

Going forward 84 and newer no collers, the post is the correct diamiter and the nut is a lock nut and only tighteded up till the shock bushing begins to buldge. They r often overtightened verses the older stuff that has it nessessary to be tight.

Also when changing this older stuff if after the shock is removed the bolt and wedges r froze in the hole free it all up dont just throw it all back togeather like that. Id say it would be a good thing to have some wedges and collers coming wirh the shocks when u order them.

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There is 8 seporate pieces of hardware that make a shock post on s pre84. 2 posts per shock, 10 shocks on the bus so it takes 20 assemblies like this for the entire chassis!!

This is fantastic.

1) Can you also include a description of where you are locating your jack stands and the process you go through to get them to take weight, and then de-weight the suspension / wheels enough to get them off?

2) What is the torque for the wheel lugs?

3) Is most of this in the 1/2” ratchet range or do we need to get a good 3/4” set?

Fratto this thread is maybe 50% or so applicable to your 97 chassis. Right? OK

650 FT LBS is the wheel nut torque. the tag steer and outer duel nuts r 1&1/2in. The nuts for the inner duels require a special square nut socket.

U should have a set of 3/4 inch stuff. My resources r limited IGo to harbor frieght and get their Pittsburg Forge hand tools stuff Very very strong guarenteed fraction of the cost, good chineese stuff (it kills me to have to admit that but there u have it) I use many of there tools and very rough with them on a daily basis for your purposes they will be perfect.

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The yellow stand is the body support point at the rear. ill gey a closer pic later, its raining. On your chassis there is a thickwalled piece of square stock going from left to right same spot. Place the body support stands there.

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Once you get the weight off the axles and get the wheels off another set of 4 stands go under the suspension at the 4 rear hubs. It does not require a 20 ton jack to get the tires up when the weight has been taken away. Dont kill yourself oversizing. Go to level low all the way up L and R rear. place rear support stands. Dump all air L and R rear. Jack and remove tires and rims install suspension stands lower and remove jack.

Ill get a couple pics of the correct tools to most easily pull tires.

Did u get yer fan hub straight?

Billy if u r reading this could u please send me a picture of those stands u picked up. Also send a pic of that off brand torque multiplier. Thank u

This old girl is starting to shape up aint she!!!

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Fratto u have stud piloted hubs and studs and rims. This Is NOT NOT NOT a stud in the photo above. It IS IS IS, the " inner duel nut"

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it requires an insert for a 1,1/2 in socket OR that specific socket.

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so first u put the inner rim on then the ninner nut goes on the stud. There r threads inside and outside of thos inner nuts.

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Once the inner rim is on and nuts tight the outer rim goes up and the outer nuts thread onto the inner nuts.

Prevo used this old school stuff on the drives for a decade after the trucking industry went to the current hub piloted that only require 1 nut for duels. prevo used these a tic past 2002 or so. Even some of the chassis with drive axle disc brakes still have old style stud piloted components.

Item 6

Tag Axle Spindles and inner oil seals.

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heres where the inner seal of the hub rides on the spindle. This is NOT the tag its the drive axle hub in the picture. big radius, just wonderful. almost impossible to mif it and nick the seal going togeather.

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Here is what u get on the tag spindle. This carries through to mid 90s same stuff and in other aspects to this day with round nuts and pinch nuts.

Look at the unbelievably stupid seal riding surface on the tag spindle compared to the drives. Zoom in on this one. Id like to meet the guy who signed off on this design. Why would u not put a smidge of a radius on this??,

Because of this regardless of who pulls a tag hub IE local shop, prevo, yourself, me, keep a closer eye on the backside of the wheel to be sure the seal isint nicked on the friggin 90° Edge on the spindle. It only holds a pint full and it can drain in a hurry if it leaks. Yes u can go in for a leaky seal and leave with 1 too. Sorry. keep an eye on it till u know its ben put good after service here.

Because of this design this procedure has M.I.F. written all over it. Be conch any time the tag hub is being removed from the spindle.

So now, how tight is tight???????

I always mention about how u should always index the hub before u disassemble it, see how mamy exposed threads u can count on the spindle before u loosin it. ITS CRITICAL FOR A NOVICE to do this on these tag hubs. The seal goes up SO TIGHT a novice might assume the hub is tight when its fsr from it. Il get the hub up put the outer bearing in and get the nut started. Then snug the nut turn the hub while hitting with a large rubber mallet snug the nut again and repeat until the 2 nuts and washer expose the same amount of threads on the spindle that u had before u disassembled it.

if u set the inner nut correctly (its a round nut) do this after u verifyed the seal is completly seated. Then turning the round nut back a tic till its free then back tight, EASY, like safe crackin, by hand,easy, feeling close, find exactly where the round nut touches the bearing, that exact spot.

Next, this is where many blow it.

Turn it back loose 50°(aprox. friggin round nut). On a regular nut its exactly 1 flat spot of the nut backed off.

If u have it good u will feel 1 or 2 1,000ENTHS of jiggle if to grab the hub and jiggle and see. AND then, after u run up the second locking nut up the jiggle in the hub goes away. That would be just about right. They say u can have a couple thousands in there tight but i think this tends to cause scuffing on the spindle where the inner races on the bearings ride.

Choice is yours either way is within spec, sorta. Do u trust me? I told u my coustomers have been refered to as test pilots. Scatterbrain Service right? LOL

Whos gonna be my next test pilot??

Oh I neglected to mention the steer axle has the same desined spindles.

When using the torque multiplier how do you measure the torque ?

Instead of a breaker bar with the multiplier u put a torque wrench. My multiplyer is 10 to 1 so i set the wrench at 65. and it clicks at 650.

Item 7

The ride height valves.

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A brief history. L to R

First one left these were on chassis until the early 90s
King of the Road ride height valves. They win the absolute best co name for the product they provide award. love that name. These r not interchageable u have to specify L or R.

next one from the left is a Haldex they were put on mid 90s chassis. All position easily available good valve. Co / product name ........ needs help

next 1 over. 1 year wonder.
knore bremse. Very short run, they suck, sorry. These things r spring loaded and even if u know that goin in the friggin thing spins out of yer finger and your posed with trial and error a few times before the new one is functioning correctly. Get my drift?? These really make problems for the novice. No wonder they didnt stay long.

Last one to the right.
Hendricson type. These came along by 2000 and I know they go at least till 12. These r great very small simple design very difficult to get wrong. the all around best choice accept for the bran name. Wouldnt suprise me to learn they r still using these.

Question one of u guys with 2016 and newer. R the chassis still using the hendricson type or have they moved on again?

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King a the Road Ya baby u have no pulse if that name dont excite ya. I need to get a pair of these on my Peterbilt!!

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heres the adjustment for ride height for your 80s chassis. These r very nice. Makes small adjustments a sinch.

On the 80s chassis with ALL copper plumbing the small stuff the 1/4 and 3/8 those r what become welded togeather over time . The bigger stuff all seperates good. Be very very careful with the 1/4 flare at the ride height valve. Have a fliring tool and couplers on hand and ready if u r changing these.

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the 83 La Mirage Shes sportin her new kingatheroads. yes sir.

Maybe a "U" Tube channel in the future?

Agreed, you need to do videos.

show me Gill. Ill do them here not on u-tube.

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Some proper bits for a Liberty Prevo. Pictured r the king a the road height valve the R6 brake relay and the 1 way check valve for the primary tank.

We r on to the front. We replaced all 3 brake relays all the rubber brake hoses all the chambers and diaphrams We also replaced the check valves on the primary ans secondary tanks the the emergency brake relay and the ride height valves on the entire chassis. Thats in addition to pulling all the hubs to the spindles inspecting and cleaning the brakes and reassembling with all new seals and oil, new brake rollers and return springs. 10 air bags and 10 new shocks r icing on the cake.

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Item 8
The 4 air bag straight axle steer axle.

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1/4 in copper line. Very correct. Still seals up after all these years.

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And the regular suspect the drag link dirt boot. Either yours is replaced or it needs to be. Some things never change.

Ok this is something special. The 4 bag straight axle steer axle. These r the strongest and best riding front axles prevo EVER put on a bus. To this day. They went away with the 83 model year what a shame.

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A happy happy 83 look at er shes glowing.

Item 9

The brake drum pilot and retaining screws.

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These brake drums r piloted to the hub and its a tight machined fit. Even after u get the tapered screws out of the drums they will be very stuck a sledge or a port a power is required to seporate them. The pictures tell the tale. Clean and sand the mating surfaces before reassembly. Every time the drum comes off this needs to happen

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These r the tapered screws that go through the drum and into the hub. These r very often drilled out to remove because of bad assembly. These r more for assembly that securement of the drum. With a newer drum and hub the drum is so massive it will cock on the hub making it impossible to mount the rim. These facilitate keeping the drum flush up with the hubso the rim goes right. They also help correctly seating the 2 opposing flanges.

Once u have the drum all the way up on the hub I go back and 1 at a time take the screws out antisieze them then reinsert them and do NOT tighten them down but rather as soon as the screw hits its seat stop right there thats enough. Go around 1 at a time and do all 5. Once u have the drum on its pilot putting the inner rim on will run it all tight. It will also capture those screws with the flange of the rim and even if they r a tic loose they can not go anywhere. This way the next poor basterd that goes to take the drum off probably wont have to drill them.

The last few years prevo put drum drive brakes they omit even using them thats good and bad. They dont get stuck but another process is needed to be sure the drum isint cocked prior to installing the inner rim and tire.

In short clean the pilot surfaces and do not rip down the tapered screws.

I came back to this thread to review Joe’s description of the work he did, and realized I never posted an introduction. Well, better late than never. I’m that greasy fella in the chair wondering what in the hell he signed up for. :)

I’ve had this bus for almost four years now. Repairs and upgrades have been a lot of fun, and have also given me the opportunity to learn new skills. I had been nibbling at the edges of some of the bigger projects, but Joe came in and knocked nearly all of them out in a little over a week. I’m still chasing a few air leaks (Joe - I replaced those low pressure switches!), but am close to buttoning her up for a good trip or two.

I generally read a lot more than I post on forums, but I’ll be sure to chime in from time to time. I really appreciate the chance to learn from more experienced owners.

Joe- R U coming to the Expo this week would like to meet up

Joe, have you seen this on "You Tube"?

https://www.youtube.com/watch?v=eEGwgzGnPCY

He works on older buses with Detroits.

His channel is growing, he is helping folks with their older buses, and he is making money, posting his work on "You Tube".

LOL, happy to see I’m not the only lost sheep!
Mark

Dont worry Mark u r not alone brotha.

John I do not have the ambition I used to and even with my newly imposed tough screening process I've employed the work out ahead of me keeps building. Glad to see a good wrench out there with a following.

I know a guy from east of KC with an old Liberty who is with us that will really appreciate the thread for sure. Thanks for sharing.

There u go Chad!! Bet hell know that cruise control