spring plate bushing R and R

[jasonlee]

Hello All,
Well last week, I was talking about my rear shocks. As mentioned, they are not the problem It is my spring plate bushings. I have replacements and started searching on how to remove the spring plate. I have found many searches covering the topic, but all are a little different.
Some say disconnect sway bar and shock, some don't. I am confused. Can anyone tell me the simplest method to removing the spring plate so I can replace the bushings? I have already jacked up the car, removed the wheels and scribbed marks locating the radius arm. I am confident I can do this repair, just need a little guidance.

Thanks

[zippy_gg]

As you want to remove any load on the spring plate you must disconnect the shocks and I suspect the sway bar.
When this is done measure the angle of your spring plate so you will be able to re-install at about the same ride height.
Also scribe the position for the smaller plate on the larger plate so again you will have a point of reference when re-installing.
That should get you started.

[gtc]

Remove the four spring plate cover bolts and the two trailing arm mounting bolts. Pry the cover off the spring plate, then pry the spring plate away from the body.
If the spring plate wont separate from the trailing arm, loosen the toe and camber bolts.

Disconnecting the sway bar and shock probably isn't necessary, but would help free things up to make disassembly and reassembly a bit easier.

[jasonlee]

spring plate cover is off, and trailing arm bolts are off, or 1 is anyway, but undone
Spring plate does not seem to want to come away from the body. I am prying, but I don't want to dent the underside. would heat help?

[GaryR]

Spring plate is most likely frozen to the torsion bar, which in turn is stuck in the internal splines of the rear housing. You can try more force, use a wood block as a fulcrum. My guess is the inside splines will release and then you have the spring plate stuck to the bar. If that happens you may need to drill a hole in the end cap and try and drift punch the bar out of the spring plate. Welcome to the world of rusty old cars.. Remember to grease the hell out of that bar when you reassemble!

[jasonlee]

thanks. I had a feeling this was going to be a PITA. The other question one of the bolts that attached the spring plate to the trailing arm will not come out. Its undone, nut removed, but it is not going anywhere. Thoughts...

What kind of grease on the bar when the time comes? Lithium?

[KTL]

Try jacking up the trailing arm a little bit. When the trailing arm is drooping with the car on jack stands, the force of the shock and/or torsion bar puts a load on the trailing arm and makes removal of the spring plate bolts a little pesky. Jack it up just enough so you can feel that the spring plate is loosely connected to the trailing arm

Also, stupid question, but have you removed the trailing arm alignment bolts? Those bolts set the camber and toe and they are thru-bolted to the spring plate. If you don't remove the alignment bolts the spring plate ain't coming off.

Grease the bar across its ENTIRE length, splines included. A good quality synthetic wheel bearing/CV joint grease is best IMO.

[jasonlee]

Kevin,
Thanks. I did not remove this other bolts you mentioned as I thought they just need to be loosened.

I will try again. I have moved to the other sit, but I can't even get the shock unbolted. Arghh

[KTL]

Ok that is where you're experiencing resistance. You can loosen the alignment bolts and just remove the nuts on the side of the spring plate. The nuts have to come off or else the spring plate is still unable to come away from the trailing arm and/or chassis.

Once you get the other trailing arm bolt out, you'll see why its stubborn. Usually the threads on the bolt, those that aren't captured by the nut, are flattened. That thread flattening demonstrates how the bolt is under a lot of stress as it clamps the trailing arm to the spring plate.

Shock bolts are large fine thread M14 and can often be really tight. Might need to get a "cheater" bar on there to loosen the shock bolt. If you have a friend with an impact gun, borrow it.

[GaryR]

Originally Posted by KTL

Also, stupid question

Apparently not, I made the assumption the spring plate was free of the trailing arm.. OP, you were trying to move the spring plate without unbolting it?? it goes back to earlier advice explaining that the arm may be under tension until it drops off the shock.. Get the shock bolt out, may take heat and a 6' breaker bar if you don't have air tools.. You won't be able to align the bolts when done as easily either..

[KTL]

Yeah I shouldn't have said that. The alignment bolts are attached to the spring plate AND trailing arm which isn't entirely obvious to somebody tackling this job for the first time.

[sailchef]

This.....

Originally Posted by KTL

Try jacking up the trailing arm a little bit. When the trailing arm is drooping with the car on jack stands, the force of the shock and/or torsion bar puts a load on the trailing arm and makes removal of the spring plate bolts a little pesky. Jack it up just enough so you can feel that the spring plate is loosely connected to the trailing arm

Also, stupid question, but have you removed the trailing arm alignment bolts? Those bolts set the camber and toe and they are thru-bolted to the spring plate. If you don't remove the alignment bolts the spring plate ain't coming off.

Also.... It will be much easier to loosen the lock bolt and height adjuster bolt while assembly is still attached to trailing arm. Lock bolt is @ 175 ft lbs torque if I remember correctly. Its a biotch when off the car. In perspective the shock bolt is only @92 ft lbs torque. You need a big breaker bar to remove and a large torque wrench to replace everything back together.







Secondly....It will be a whole lot easier if you can manage to get the spring plate free from the outside end of the torsion bar first. Due to lack of space, seperating the spring plate from the torsion bar after the T-bar comes loose on the inside of the tunnel is no real fun but can be done.

Good luck, take your time, and ask questions. This board will get you thru any projects you are up to taking on.

[jasonlee]

thanks for all the info.
I managed to get the spring plate detached from the trailing arm once I removed the camber and toe bolts, popped right off. then the spring plate came away from the body, with the....you guess it the torsion bar. Looks like I will drill the end and use a drift to get it out. I plan on taking my time, and hoping i don't lose my cool. Sadly no air tools. I did have an electric impact wrench, but I broke the chuck on that.

[GaryR]

Don't be afraid of force to drift that bar out, you wont hurt anything.. Support the arm, 3 LB hammer, 3/8 or 1/2" punch 12" long to clear body, swing away! You can also grab the torsion bar with clamps to restrict movement but trust me (have done it 10x) just get it out and deal with repair/modification afterward. You may find it's been rubbing badly and want new bars anyway.. How are the bearing end caps, I bet they are garbage...

[jpnovak]

The torsion bars are often stuck in the spring plate. The old grease is like glue holding them in. You can clamp a vice grip on the torsion bar and then pry against the vice grip to push the spring plate off the torsion bar. Its hardened spring steel. You may nick the paint but not the torsion bar itself. Cleaning up and painting the ends is much easier than welding the end of the spring plate.

If this does not work, heat the end of the spring plate where the splines are and continue to pry it off.

If that does not work you have to drill the end and use a drift and sledge hammer.

If that does not work you have to cut the torsion bar. bimetal blades are almost, barely adequate for this job. A cut off wheel is much faster.

[jasonlee]

Thank you. I have a drift and can hammer away. I may try and pry against the vice grips. It appears I may have to repaint the torsion bars anyway. In the end I may just put new bars in if they are too far gone. What is the stock size of the rear 27mm? and would putting in a 29mm, just slide into place? Really would love to get this finished by the weekend. The only other thing is getting the other shock undone. Heat and a breaker bar I hope will be enough.

[jpnovak]

Just make sure that if you are using the drift you have to support the spring plate such there is room to push the TB out the backside. I have a section of pipe with a slot in it that fits over the torsion bar and seats against the body. This allows the force to move the torsion bar rather than the spring plate. A block of wood can also work but gets hard to hold all of it together and get a good hammer blow without hitting the QP on the outside.

REmember, your drift will have to go through the access hole in the QP. Don't Slip!

The rear torsion bars usually do not have rub marks in them. That is typically reserved for the front. However, the outer spring plate cover can rub the spring plates and put a groove in them. This is extreme wear cases. If you have a groove worn from metal-metal contact you should replace the spring plates. I don't like welding spring steel in that location.

The TB should be a 24mm. I always think the rear can use more spring rate (larger torsion bars). It really depends on your driving style and what size you are matching on the front.

btw, if the rear bushings are shot. The fronts will be too. Best to consider a complete suspension refresh along with corner balance and alignment. The car will be transformed.

[jasonlee]

Jamie,
I don't see any extreme wear case yet, but that remains to be seen when I get the spring plate off. I am going to try your first suggestions pry against vice grips and some heat first, before I start hammering away. I have done lots of things to my car, but this seems to be the biggest I have tackled, or at the very least the one that I was most apprehensive about, especially maintaining original ride hight etc, but seems open I have it all apart it is straight forward, its just getting to that point.

[KTL]

Original rear torsion bar size is 24mm on the SC. Any size replacement torsion bar will slide into place. The bar diameter beyond the splines is where the size change occurs. The spline diameter itself is the same on all the bars, be they original or aftermarket. By the way '87 thru '89 bars are not the same as SC bars- they're longer (and I believe spline count is different?). So don't make the mistake of purchasing a set of those

After you pound the torsion bar out, you can clean up the splines in spring plate tube with a tiny file or sharp pick.

[RD911T]

When I was taking apart the suspension on the 71 I'm restoring, one of the torsion bars was stuck good. I drilled a small hole in the TB cover on the spring plate and shot some Kroil in there and then rotated the spring plate to get full coverage and penetration. It took a couple days, but it loosened up. A small hole may be easier to cover with some JB Weld or silicone.

If you don't want to drill, you could get a longer spray adapter and spray some Kroil or PB Blaster in from the inside of the spring plate.