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63-82 Rear Trailing Arm Rebuilding

158K views 240 replies 64 participants last post by  gtr1999 
#1 · (Edited)
:crazy: Ok here is one job I get a lot of questions on. First thing I find is that a lot of guys are intimidated by this job. Once you understand corvette rear bearings the mystery will be gone. You'll be able to decide if you want to buy the tools and try the job or farm it out. Now the tool cost for a set of arms is more then farming them out so think about what your plans are. If you want to join the dozens of Arm Rebuilders out there buy the tools - but do the job right. This post will have pictures of various jobs I did so don't be surprised if the arms look different.

To do this job follow the GM manual procedures. I do some machining to my jobs that others don't. Take it for what it is and make your own choices. One thing I already know is guys have been asking questions now as opposed to just having the jobs done. Also ask your rebuilder if they supply any job reports and pictures on their work. I like to keep the car owners involved and make sure they know what was done with their arms.


Here are what your arms may look like once you get them out. I always rebuild them off the car but they can be done on the car. I would never do it that way unless I was stuck out of state on the road. Doing them on the car will not address the front bushing for dry rot and play. Trying to get an accurate setup will be difficult but getting a "good" job with GM specs up to 008" endplay is possible- if that is what you want ok, I like to dial them in much tighter so there is no lateral play and the bearings are smooth.





Here is a 64 arm. Remember the 63-64 and some 65's had drum brakes.




Look them over for rot, being bent, and look at the front bushing for dry rot.



I use one of those spindle protectors and either press or hammer the spindle out. If you hammer them out place something to catch the spindle. Don't worry about the bearings as they will be replaced anyway. If you have one that is really rusted the press and some heat may be the only way to go. Also the spindle nut should come off and the tool thread on without a problem. Many times these have been worked on before and the threads are already shot and a new spindle is needed.

REVISION- I have not used a press on any arms now in over 15 years. A 4-5 lb mini sledge and the spindle knock out tool should be all you need.



Here we have parts to one arm apart and cleaned up for inspection.



Here I found someone was in here before and installed the outer seal backwards.



Once stripped down, I remove the front bushing


Drill the flare out and use an chisel to remove. I used to put these in a Bridgeport mill but a large step drill works as well.







With the arm apart, I blast them to the metal and POR15 prep and paint them. I top coat with a satin black.




I use only rubber bushings, no poly for me. The rubber have to be compressed and then flared to correctly install them. I have found all kinds of crap work in this area, some have even left them unflared!


Here is the tool I made. Works good. There are a few on the market, some good -some junk.



Here are what mine look like



 
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#196 ·
Well I found another Bubbafied part. The same arm that had the broken bracket had a hammered on spindle spacer.
I can't figure out why someone would do this, it was purposeful since the spacer is hammered 360* and the large bell end is really beat up. The spacer was probably junk when they worked on it and just made it worse. You can see the gap under the race, no way in the world someone would be able to setup the bearings with a spacer like this. I have some good used GM or new aftermarkets here to solve the problem. For those of you rebuilding your bearing be sure to check and parallel grind these otherwise you are going to have all kinds of setup issues.






 
#199 ·
I was asked about Tom's 31 spline outer axles and didn't see any pictures of them scanning over this thread so I figured I would add them so those who want to see what they look like. They come in dual bolt patterns for stock 7/16 studs or 1/2-20 x3" ARP's. Typically if I am building a 31, then I use the 1/2 - 20's for a bit more strength. I also machine them down to size. The inner flanges for these can be 1350 or 1480 size.



Here is a stock 17 next to a 31




31 in smooth jaw vise




Dual bolt pattern. I use the 1/2 typically and tap the 7/16 to fit the rotors.










1350 inner flange

 
#202 ·
Birdman, long time how is retirement there sparky?

No I don't recall if they were much lighter. They are a good product but not one I would typically use. I have run new stock arms at the drags and they were fine. I don't like the way the bolts are with these arms, unless they have changed them since I did that set?
 
#207 ·
Very true Brian. Tom's stuff has been proven over 40 years now and made in CA or ID.

There is a vendor now pushing their new 9" IRS which I think is aimed at capturing Tom's business. It will be interesting to see where that project ends up and just how strong it is once subjected to a lot of abuse. Unlike some "snakes in the grass" on other forums I have no intention of going in that direction.
 
#208 ·
A Ford 9" inch is actually not that strong in stock form.
Safe to 400-425 HP & 400-450 Ft/lbs flywheel torque in a 3,400lb car.
The Very Best 9 inch was used in the 428 Super Cobra Jet Mustang.
A few Grand Torino's go the same spec 9 inch diff.
You have to start with all aftermarket parts to build a Strong 9 inch.
Not so cost effective then.

The pinion offset - dropdown is much more than Chevy used.
 
#210 ·
Not sure tonight Gary.
I can tell you its real easy to build 900 HP today with a Single Turbo Charger used, Correct intercooler intact, and right fuel system.
The next generation of young Corvette owners will want HP.
The stuff on You Tube is real.
I worked on 2 separate Turbo projects this past summer with my bud Ed.
Not even drag race & stellar results on the street.
347 cubes on boost runs like a 800 ci BBC.
 
#211 ·
Yes Brian, I should rephrase my last statement. In today's world going over say 900hp I am not sure the best setup for a C2-3. I have my 12 bolts in vettes up to about 900hp.

I think the question is just how many young guys are going to continue to run c2-3's? I will guess not many compared to the past 40 years. The new cars out perform them all day long and cost less on the used market. Would you spend $50k on a 300hp base C2 or a good used modern muscle car? I don't see a lot of younger guys walking around Carlisle. some yes but enough to support the hobby say over the next 10 years?
 
#212 ·
You can set the Boost on Turbo charged cars- engines to hit super hard or soft initial.
Most choose soft hit so to speak.
Believe it or not there are a surprising number of Ford guys that like my C4 Corvette.
20-48 years old.

The Body lines of C3's are timeless.

C2's are exclusive.
No one gets into a C1 or C2 cheap.
Bring $50,000 -$200,000 Cash.
 
#213 ·
I don't think its Over Gary.
Some of the guys that are Ford Racers are past & present NHRA NMRA Champions.
They admire a Corvette as driving machine.
And they have 2,000 HP or more in their race cars.
Its funny...I bring up Hellcats & GAY POS comes from them aloud.
They Laugh.
Standing around my 87 C4 roadster talking....;)
 
#215 · (Edited)
Glad to hear a young man in Europe interested in these old cars. I have worked with fellow corvetters worldwide. The age range I believe still hasn't shifted to the younger guys and there are several reasons for that but that is not what this thread is about.

I do not have a video, I just don't have the time to setup and make one. Keeping these posts up to date with all the pictures takes me time and now with the possibility of losing 3rd party posting I don't know if I will try to recapture the past 10 years I have running now.

This thread will help along with the factory manual. Many of the videos I see on places like YouTube are not how I build them nor would I recommend what I see.

What point are you at with the rear bearings? Do you have them apart or are just in the planning stages now?
 
#216 ·
I started reading this thread again, first time in a while and I didn't go through it all again. 10 years, some guys are not here anymore, some controversy with various opinions back in the day, real corvette drama!

Ok so I don't know what stage you are at, what experience level your shop has, and if you have access to a machine shop?

I have coached a lot of guy through this and made some changes to my procedures since I started these thread 10 years ago.

So lets say for discussion you have the arms out of the car. Rotors still on. First I would check the runout in the rotors and endplay in the bearings before you take them apart. Measure the thickness of the rotors to see what they are and if you need to replace them. If they are still riveted on then no one was in there before which I prefer since many of the arms I work on that had been worked on before were damaged by previous attempts- as the pictures here over the years show.

Once you know about the rotors, remove them. If the runout was under 005" and the rotor still good - mark them to position on the axle. It may have dial them in later. I never worry about that because I won't send out arms with 005 runout- I get them under 0025"-without machining the rotor or axle flange. This is one application I don't like taking a chip on. As you can see I dial them in and bolt them on. The runout doesn't change then.

With the rotors off look over the arms. Look at the rear overlap seams and feel inside the opening for bulging indicating rust. If you fine a lot of rust toss the bare arm. In the long run you are better off with a USA made arm. They are very good. Look for dents up by the front bushing, signs the arm was bent during an alignment.

Flip the arm over so the axle nut is up. Remove the cotter pin, spray some penetrating oil on the nut to help remove it. Look to see if the end of the axle was hammered on in the past and mushroomed over. If extreme you will have to dress it before removing it or you will strip the threads off the axle and it will be junk. In a good case the nut comes right off. remove the cupped washer under the nut, this throw out, you need to use a new one. The flange will then slide off the axle. These I recondition to better then new but that is a whole different process. You can check the tapped holes to make sure there are no thread issues. I use a long bar and pop off the inner shield, I replace these too.

With the axle now ready to be removed I DO NOT use a press any longer. Too much chance of breaking parts or getting hurt. The axle should be held in with an interference fit on the inner and outer bearings. The inner bearing is actually holding it in. I use the axle knocker tool available from any vendor for about $15. You can make one if you like but the time to make it is worth more then just buying one. These are made to bottom on the axle to protect the threads. Now hold the arm at about a 45* angle on your workbench with your left hand and using a 4 to5 lb mini sledge hammer drive out the axle. Takes about 5 -6 heavy shots to drive it out but it will work. I gave up the press and did 100's like this. Now this is important,when the axle comes out look to see if the outer bearing is still on the axle. It should be- if not then the axle is undersize most likely and junk. Save the shim and spacer. I machine the spacer and then check them, sometimes the large end will bottom on the axle shoulder step and if so it's no good. The faces of the spacer are beat up so I parallel grind them. The shim are too but they are never going to be the same size when setting up new bearings.

I am getting tired of typing is this still interesting?
 
#217 · (Edited)
There was a question on how to setup the bearings so I will type some more.

Once I have an arm apart I check all the parts, make sure the arm isn't bent or rotted, iron parts not bent or damaged, axles checked for diameter and threads- look back on this thread for that info. Check the bell spacer and machine it, then setup the bearings.

Now here the way I do it will probably not be the same as many of you will be able to do, unless you can use a surface grinder. I have complete stock of shims, ground to size within 001". The kits you can buy anywhere come with shims but not close enough in most cases to dial in the setup I use.

First lets look at the spec, 001-008" endplay- that is the movement of the axle within the bearings- in/out movement if you grab the axle by a stud and push/pull on it. At 003" endplay I can move the axle in/out. It is in spec but not what I would use or recommend but it's in spec and some will leave it.

I made a fixture to hold the bearing support, you can see it back a few pages. A quick note about "fixtures" some out there throw that term around to try and intimidate a DIY not to try a rebuild at home. My "fixture" is a piece of flat aluminum I bored and drilled 4 holes in so I can bolt on the bearing support. Get my point here?

So with my fixture I am setting up the bearing with them in the vertical plane. I use a common setup tool, which is nothing more then shaft machined to duplicate an axle - only undersize so the bearings can slide off. The one I have has a knurled handle as well and works great.

If you want to "seat" the new bearings you assemble them on the setup tool without the bell spacer and shim, just the bearings. Snug up the nut so there is some drag on them and slowly rotate the tool a dozen times CW & CCW, tighten and do it again, do it 3 to 4 times then take it apart and install the bell spacer and the thickest shim you have. Torque the nut to 100 ft/lb and only use a light oil on the bearings. I use machine light spindle oil. Once you hit 100 ft/lb mount an indicator so the tip is on the end of the tool. -0- the indicator after putting preload on it, the push up and read the amount of endplay in the bearings. Say you have a 150" shim in place and you have 020" endplay, remove the 150 and install a 130 and recheck it. Lets say it now read 002", the magic number everyone claims is correct since the WWW started and forums started up. You can stop there if you like but I never do. When you move the tool look to see if the indicator first jumps then settles in at 002". If you leave it at this point you may find the final setup is about 002 more then you expect. What I do at this point is start to grind off 0002-0005" until I get to the point where there is no lateral play or the initial indicator jump- yet the set up is perfect. Now the bearings are done and ready to install. For setting up Tom's 31's I go into a preload setting.

Another thing I see a lot is axle flange runout. These axles were not fine faced since the rotor was to be riveted on and then final faced. There can be up to 010" runout in an axle flange and that does not mean the axle is bent. If there is no sign of an impact on the axle, no hammer marks or cracks, chances are the runout is the same as it was new. They can be faced but in this application I don't like to remove a chip. I can dial in these to under 0025" as explained in previous posts.

Ok that's all for typing now. If you still are lost post your questions.
 
#218 ·
Thank you for taking the time to write down all this information!! :cheers: Should I visit the States at one point in time, I will try and buy you a beer (or several ;) ).

We (the shop and I) are at the stage the assemblies have been taken apart and first test fitting if the new bearings and seals showed the apparent mismatch that led to my post.

I inquired a regional supplier of corvette parts (only 2 or 3 in my country) and he has two complete sets of Timken USA bearings and seals in stock. I will order those, provide the shop with the tutorial you have just written and then but them beer too. It's the best I can do for now, hah!

Of course I'll keep you posted on progress.
 
#219 ·
Update!

Well, we finally managed to finish the job :partyon:

Took me a while to get back here; sorry about that.

Can't tell you yet how she drives now; broke two brake bleeder nipples (two calipers of course :bang). Having a go at replacing those tomorrow.

 
#220 ·
Come on Man, you didn't paint the supports, your customer isn't going to like that!!!!!:thud:

Using GW arms, did you have to drill the support and brackets larger to use the bolts they supplied or have they changed them since the last set I built? I personally like the stock arm bolts with knurls much better but those will work.

How about tapping the axles to bolt on and dial in the rotors?
 
#221 ·
Ah yes, I fixed that later on. Not really efficient, but hey: after breaking those bleeders I suddenly had a whole new time schedule ;)

No drilling or tapping was required, so I guess they have fixed that. I did have to change the bushings, because the ones on it had a sleeve with a too small diameter for the stock TA bolt. good thing I ordered a complete VB&P poly kit a while back.



 
#223 ·
Gary,
The fact that you would take the time to pretty much retype so much of what was stated earlier over ten years is a testament as to why you are one of our most valuable assets!
My hats off to you my friend!
And to the young man in the Neatherlands...
You have just been taught by one of if not The premier Corvette suspension and steering gurus!
A Win/Win!!!
Ya gotta love DC!!!
 
#224 ·
Thank buddy, I suppose you are all settled in FL now and away from the snow and cold? We just got the tail end of the storm that went through the South and it was enough to regret the next 3 months of Winter up here!

Be safe and enjoy the Southern Winter!:thumbsup:
 
#225 ·
Gary,
I'm a novice who recently accuired an original 64 and I'm currently rebuiling the trailing arms....your posts on here are great. Luckily those 54 year old bearings and bushings were just starting to fail before any thing else got damaged. Yesterday I was putting in the bearings and measuring for tolerance. Man, that was frustrating. Now that I found your posts on here I'm going to knock those bearings out and give it another go and see if I can't close the gap down just a touch. Really appreciative of you're contributions on here. Hopefully I'll get this knocked out before spring is past.
 
#226 · (Edited)
You can do it, do your homework, understand what you want to happen, use the correct setup methods and tools, and you will be fine. These are not special bearings as some will try and tell you. Don't listen to those that will tell you can not do them at home. You can but you will need the tools and access to a surface grinder to really get them dialed in.

If you have a problem contact me directly
 
#227 ·
Hi Gary,
I've read through the entire post and I have some questions before I get started. I also have some pictures which I am not experienced enough to know if the part should be replaced. It looks like I can only attach one picture. I'll try attaching the others in separate posts.
Questions:

  1. Are you still using the Timken bearings? I have access to a bearing supply company through my company, therefore I can whatever bearing you recommend.
  2. Are you still using the Timken grease as in a later post?
  3. In one the posts you said you use "CR" seals, I was not able to find CR. I assume they were bought out by another company or went out of business. What are you using now?
View attachment 22577
I believe this is the original spindle. I measured the area and it is within spec from one of you posts. Should this be trashed?
View attachment 22585
 

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