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Adjustable Torque Rods

cmsuter

cmsuter

Member
Joined
Feb 11, 2019
1992 244. I've read some conflicting info. Lowered my 240 on IPD springs and recently did a M47 swap. Upon acceleration and deceleration I get a clunk like there's a lot of play in the rear end. All the bushings are about 2 years old, poly (U-joints are all new as well). I also have some vibration in lower RPMs.

I have read some people say when they lowered their car that they needed adjustable torque rods and some people said they didn't. I understand that they are used to fine tune the pinion angle, but I've read some people say it isn't quite as vital as when dealing with a 1-piece drive shaft. So what's the dealio? Could this be my issue?
 
The torque rods can be used to adjust the pinion angle as well as the position of the axle inside of the wheel well front/back. The axle trailing arms mount to the underside of the axle creating a pivot point and then torque rod attach at the top, if you shorten or lengthen the torque rod it'll pivot the axle forward and back to an extent. When you lower the car the rear trailing arms flatten out effectively making the wheel base longer so if the wheel is no longer centered in the wheel well you would have to shorten the torque rods to bring the axle forward, at that point you should also be checking your axle alignment left/right, with the panhard bar attached as the suspension compresses it'll push the axle towards the passenger side of the car, lowering it does the same. Not sure if the iPD springs drop the car enough to affect the rear suspension geometry enough to create any issues. Driveline angles are more vital with a 1 piece shaft especially if you're trying to prevent vibrations, a 2 piece drive shaft has a carrier bearing and rubber bushing eating up a lot of vibrations and you can shim the bearing to more easily set your angles as long as your trans and axle angles are right. While I don't know suspension geometry that well I imagine the torque rods also help prevent axle twist which you mainly see in older American stuff on leaf springs, maybe a bandaid to take some stress off the half hollow trailing arm bushings :e-shrug:
 
If you suspect pinion angle is off measure it before getting torque rods, I didn't need adjustable torque rods with just IPD springs even with a 1 piece driveshaft. That being said it's not going to cause a clunk, that's movement from worn parts or loose bolts.
 
We'll something is loose if your getting a clunk, I just posted the two common clunking problems. Why can't you jack it up and figure out where the clunking is coming from? Maybe it's in the diff... Who knows? Clunky clunky clunk. I know when I had bad wore out trailing arm bushings when I would get on the gas the car would go left or was it right from the rear steer dear.
 
sbabbs said:
We'll something is loose if your getting a clunk, I just posted the two common clunking problems. Why can't you jack it up and figure out where the clunking is coming from? Maybe it's in the diff... Who knows? Clunky clunky clunk. I know when I had bad wore out trailing arm bushings when I would get on the gas the car would go left or was it right from the rear steer dear.
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but but but All bushings are fresh polyurethane. I double checked that everything was tight and it is.
 
James M said:
but but but All bushings are fresh polyurethane. I double checked that everything was tight and it is.
Click to expand...

Don't be a dick. I'm not ruling out that it could be the bushings. But it isn't irrational to consider other sources elsewhere since they are fresh and tight.

I jacked it up and tugged and pulled rotated and couldn't find it. I have a friend with a lift so I'm working out a time to go put it on a lift and actually run the car and try to see what's going on.

Regardless.... the point of this post was just to get everyone's opinions/experiences with adjustable torque rods.
 
Don’t polyurethane lower trailing arm bushings make the rear axle bind? The original bushings have cavities to allow the axle to twist to an extent, the bushings with voids are a horrible design but the best Volvo thought up in 1980. Now BNE offers spherical bushings to allow the axle to move as designed with longevity in mind. Maybe it’s binding and creating that clunking? There’s really not a whole lot that could clunk under there. How’s your trans mount
 
My exhaust clunks when I go through a diagonal dip that rocks the car side to side. I built a 2.5" exhaust and went over the axle so it's my fault, but still.... One more thing to check. I just didn't leave enough space for the exhaust tubing to swing around and occasionally it hits the floorpan.
 
Radtap said:
Don?t polyurethane lower trailing arm bushings make the rear axle bind? The original bushings have cavities to allow the axle to twist to an extent, the bushings with voids are a horrible design but the best Volvo thought up in 1980. Now BNE offers spherical bushings to allow the axle to move as designed with longevity in mind. Maybe it?s binding and creating that clunking? There?s really not a whole lot that could clunk under there. How?s your trans mount
Click to expand...

Yup. It doesn't lock up the suspension tight, but poly TAB's will cause a bind in the rear movement. Those bushings need to be free to flex in all directions except forward/backward. Poly will make it harder (than stock) to flex in all directions.

But it's likely not a big deal unless you are chasing down 10ths of a second lap times on a race car.
 
cmsuter said:
Don't be a dick. I'm not ruling out that it could be the bushings. But it isn't irrational to consider other sources elsewhere since they are fresh and tight.

I jacked it up and tugged and pulled rotated and couldn't find it. I have a friend with a lift so I'm working out a time to go put it on a lift and actually run the car and try to see what's going on.

Regardless.... the point of this post was just to get everyone's opinions/experiences with adjustable torque rods.
Click to expand...

Just having a laugh, my apologies.

Having on a lift should help narrow it down.

I did not need them with IPD lowering springs, but did with BNE adjustable perches and shorter springs.
 
cmsuter said:
2-piece. Carrier bearing and rubber mount are both new.
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Another DS related issue could be the slip yoke. If its sticking, that could also be it.

My truck does similar, but mine is due to worn diff gears, because they have been towed on alot. You could pull the cover and check for excessive backlash with a dial indicator.
 
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