Torsion Bar Compatability? (I Searched!)

[Mulisha620]

Hey I looked on the forum for a while but couldn't find an exact answer to my question, and was wondering if you guys could help me again-

 

I was under my 620 taking the leaf spring off and I happen to look up and notice, that both of my torsion bars have been blown out.... As in the bracket at the rear of the torsion bar that's held against the bolt was bent back at a 90 degree angle on both bars..

 

I'm sure you all are wondering why I wouldn't have known this was the case, but the last time this truck moved it was towed to my house on a flatbed trailer. It was lowered as it was and to add to that the tires were completely flat. When I was watching the triple-A guy pull the truck up onto the flatbed I remember it getting caught up but then breaking loose and continuing up the ramp. Now I realize it wasn't the tranny crossmember, it was my TORSION BARS!!

 

So my question is, what do I need to look for to replace these? Are all 620 torsion bars the same or are they different lengths due to long bed/king cab?

 

Here is a picture of the damage

 

And here is a pic showing the other side too- The other side isn't as bad, but the retainer piece on the bolt that gets held by the bracket on the back of the torsion bar, is barely hanging on.. So I am planning on replacing both torsion bars..

[datzenmike]

Remove them, hammer straight and install. Read up on it here:

 

http://community.rat...ook-here-first/

 

 

About 1/2 way down page one.

 

]2edeye, Please make a note that the link to the 620 has the FSM's that everybody with a 620 should have downloaded and to donate for the privilege of getting them Cheap or Free!

 

Makya, I'm borrowing your post :)

 

Torsion bar adjustment bolts

 

Torsion Bar Re-Indexing

 

So I guess I'll start with why this needs to be done and seeing as how a picture is worth a thousand words....

 

and a quote...

 

Redeye, I feel pretty confident that the difference bewteen one spline and two, adjusted only with the slop taken out is 7/8".

 

 

 

 

The first thing to do after jacking up the truck and putting jack stands under it is to mark you arm and frame with a sharpie to let you know your starting point.

Then move the rubber boot back so you can access the c-clip.

 

 

Here's a shot of the clip. I was able to get it off with a couple screwdrivers.

 

 

After you pull the c-clip tap the arm back with a hammer until it pops loose. At this point, if your arms are still in good shape you can rotate the arm and reinsert the torsion rod one spline up.

 

 

Torsion arm assembly

 

 

All bent back into shape...gotta love steel

 

 

Final clearance. I gained about an inch rotating it one spline. I don't think I'll be ripping that bolt out anymore

 

 

All in all it took about 20 minutes and that was mostly cause I used scissor jacks....

 

 

 

 

How to Reindex Torsion Bars

 

in front of the middle crossmember, you pull the boot forward to reviel the lock ring

 

 

Work a thin screwdriver into the edge of the ring. It will be tight. I had to work the angle back and forth while occasionally tapping the back of the handle with a hammer

 

 

Once you get under the ring, work it out slightly. Do not pull the screwdriver away or the ring will pop back on

 

 

After you have worked it off part way, use some pliers to pull the ring off the rest of the way. Be sure to still keep the screwdriver under the lock ring

 

 

Tap the rear arm of that holds the adjuster bolt out of the crossmember. Hang onto the torsion bar. It can slide out at either end. I was able to feel the splines in the end of the bar and I moved it two notches. edit:(but you only want to move it one notch!) The reindexed bar is on the right.

 

 

after the bar is reindexed, just hold the lock ring up and hit the back of the ring with a hammer. It pops on real easy. Put the dust boot back

 

 

Nice pic's of the snap ring Bleach :)

 

 

Picture added by datzenmike 21/04/10:

 

 

 

 

Another method

 

just remove the anchor bolts then remove the nut on the A arm up front almost off then pound it out w/o hurting the threads

me and Icehouse did his 521 truck. We NEVER removed the c clip from the back

we just pulled the torsion bar from the front A arm and reindexed it there. Had to jack up the wheel to get it to reinstall. We never wanted to take the c clip out.

[Big Schlink]

I have a friend who made A jig and tested a bunch from different trucks. He was looking for tunability in his dirt track race truck. If I remember right he said they were all the same. I will get in touch with him to verify. It may take a few days. I'm sure someone here knows.

 

 

[datzenmike]

You can't swap L to R with them. Disc brake torsion bars are different part number but may fit, different rate??

[Mulisha620]

Damn you guys are good.. Thank you for the quick reply-

 

I will be pulling those out then, and I'll try to straighten them-

 

If for some reason I can't, or I screw up trying to fix them (This won't happen but god only knows.......) Do they all swap out?

 

Because right now at my disposal I have: A 76 or 77 620 parts truck a few towns away, I have talked to the guy because I was about to go get the leaf springs out of it- And the 81/82 720 that is in my buddys backyard, its a 2 wheel drive truck, will they torsion bars out of the 720 fit my 620?

 

Because if the 720 torsion bars will fit I will grab them as extras....

 

Thank you guys again for the heads up-

 

(I am pulling the leaf springs out of the 81 720 tomorrow morning, and putting them in my 74 620.... They WILL fit right? LOL I know I've asked that before)

[datzenmike]

All 520/521/620/720 2wd and 4wd springs are the same length and will fit. They may have more or less leaves and may or may not be stiffer but they will fit. Get the U bolts in case they are different length. Take WD-40 and a 2 foot long pipe to put over your ratchet handle to give more leverage getting the nuts off.

 

 

Torsion bars:

Get the '76 or '77 bars for a sure fit.

 

I would have said the 720 bars are different but I see that up to 12 '82 they share the same number even the 4x4s. The 720s might work but I don't know, to be safe get the 620 ones.

[yello620]

What might be mis-understood here is that you just need to straighten or replace the bracket on the end of the torsion bar, not the entire bar. So spring rates dont matter if you just fix the bent part and leave the torsion bars in the truck.

[Mulisha620]

AWESOME!

 

Yes I am planning on fixing the bracket on the bars that are in my truck now- Shouldn't be too big of a deal.

 

Is that something you would use some heat on (Torch?) or just pound them flat while they're cold?

I was planning on finding a piece of steel stock the same thickness as in the inside diameter between the steel plates that make up the bracket, sticking it in between the plates and pounding them flat.. Anyone know of a different/easier/better method?

 

And I am also now planning on grabbing the torsion pars out of the parts truck too now, I was planning on making a trip over for some other things..

 

Thanks again guys-

[yello620]

Before i would remove them from the truck, i would get under the truck with a BFH and see what happens. I have straightened a few sets of these(long time ago) and dont remember them being very hard to straighten.

[Master-O-Turbonics]

Take WD-40 and a 2 foot long pipe to put over your ratchet handle to give more leverage getting the nuts off.

"official procedure" should include the statement "You should never do this, but"

 

 

[datzenmike]

Also keep your face out of the way in case the ratchet slips off. (do not ask)

[Mulisha620]

I got em out the other day- Much Much easier than I thought I would have been- I havent tried pounding them back into shape yet though-