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July 2013 update

I have a set of Tubular Trailing Arms in to build. These are pretty nice, I guess there was an issue with brackets in the past and that is corrected. They come with "johnny joints" in place of the stock rubber bushings. I can't say I've had any problem with good rubber bushings for the past 40 years.

They come with larger 7/16 bolts they use over the original 3/8 kurled studs that are used in the stock and offset arms.
The arm holes are drilled oversize so the bolts are loose fit, the caliper bracket holes have to be drilled larger as well since they are 3/8". Once it's all torqued up it should be ok but I like the stud better.

With that said I'll leave it up to you if you think these are what you want. They look super great & are strong but I have never had a stock or offset arm fail - unless it was impacted and/or rotted. I have new stock arms on my street vette and my son's drag vette and they work fine.




Here are the supplied grade 8 bolts and locknuts





Front bushing. I use stock rubber in all my cars and like them. I haven't tried these in one of my cars.



Bolts won't go through a 3/8 hole, make sure you want to drill your originals out otherwise get another set of brackets.



Supports may need to be reemed too



Pretty loose in the arm, I don't like this part at all.

Gary, did you happen to weigh these, or know how much lighter, if any, they are?
 

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Discussion Starter #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?
 

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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?
6 more months.:D

Just putting the car on a diet, and mulling around ideas.

Do you know if Tom still makes those aluminum rear caliper brackets? I bought some Willwoods, and would like to add those first.

This aluminum fetish is spendy.:surprised
 

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Discussion Starter #204
You can call him but I think those a long gone now. He will be closing in the near future so I would get anything you need now.
 

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You can call him but I think those a long gone now. He will be closing in the near future so I would get anything you need now.
I Refuse to build any rear diff for High Performance & Drag Race use with China parts & Sign my Name on it Gary.

Looking at and end of an era unfortunate.

Next phase is one off fabrication.
 

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Discussion Starter #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.
 

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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.
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.
 

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Discussion Starter #209
Time will tell about this new setup. I agree with you that quality parts need to be used. Tom always liked the 12 bolt conversion, it would still be my choice as well for a vette IRS.
 

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Time will tell about this new setup. I agree with you that quality parts need to be used. Tom always liked the 12 bolt conversion, it would still be my choice as well for a vette IRS.
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.
 

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Discussion Starter #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?
 

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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?
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.
 

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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....;)
 

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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?
Young guy here... from abroad too... my shop and I are trying to do a proper bearing replacement, whilst going to Global West TA's.

Since everthing is here in The Netherlands, I can't (or won't) ship everything to you. Do you happen to have an instruction video or document showing the way these assemblies are supposed to be put together? Or know a few good links?

My shop is eager to learn more about US vehicles, but does not have much experience with them (except for the occasional Euro US vehicle). Owner did restore several classic British cars and I trust him to be able to do this correctly, given proper instructions.... which seem to be quite hard to find as my Haynes repair manual does not seem to regard this job worth much describing.

Many thanks in advance!
 

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Discussion Starter #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?
 

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Discussion Starter #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?
 

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Discussion Starter #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.
 

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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.
 

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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.

 

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Discussion Starter #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?
 
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