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Old 02-07-2019, 04:41 PM   #1
moustacio
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Default 7xx/9xx Large Torque Rod Bushing Installation

Hey everyone,

Just had to do some service to the rear end of my 88' 745. The large, oblong/odd shaped rear torque rod/arm bushings gave me some trouble at first, then I found a nice way to install these. The following information should apply to any 7xx/9xx series car with live/solid rear axle.

Using the AutoZone ball joint u-joint service kit I was able to install these bushing quite easily. I'm sure there are other tricks and that out there but I could not find any information about these and thought I would write this.

Pressing them out is not too bad. On installing, after destroying one of my bushings, I first pressed the bushing into the 2.75" ID receiving tube in the press kit with the aid of some silicone lubericant. (I tried dish soap on my first failed attempt and the silicone lube seemed to work much better for me, but maybe someone can weigh in here) After that it was really just a matter of finding the correct pieces in the kit and my own tools to press the bushing into the torque arm. Really didn't have to use that much force at all and the bushing didn't seem to deform much during installation.

Another note to mention is the positioning of the voids of the bushing in relation to the torque rod. After lining everything up perfect the bushing rotated by the time it was pressed in. To resolve this I put a suitable bolt through the bushing, tightened it up fairly tight, and was then able to easily rotate the bushing to the correct position with a a wrench. (I used the nut and bolt from the front strut rod I had around)

Hope this maybe helps someone and if I need to clear anything up or if more information is needed please let me know eh.
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Old 02-08-2019, 03:06 AM   #2
tintintin
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Good info, thanks!


What is the correct orientation for the bushing?
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Old 02-10-2019, 12:45 PM   #3
moustacio
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Hey thanks,

The orientation of the large bushing is such that the voids are in line with the length of the torque rod.
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Old 02-10-2019, 01:00 PM   #4
v8volvo
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Good info, thanks for sharing it.

What kind of difference did you notice with the new bushings vs the old? Symptoms that caused you to replace them? These are visibly deformed on my '86 745 but still intact and don't seem to be causing any functional faults so I have not been motivated to change them so far.
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Old 02-10-2019, 02:04 PM   #5
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A piston ring compressor around the bushing really helps compress them slightly and it helps guide them in straight.
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Old 02-10-2019, 03:19 PM   #6
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Hi v8volvo: I've read that these bushings don't go out very often. However, for me the difference is night and day. I had been trying to track down vibrations and the rear end was all I had left so I ordered all the bushings. I first replaced the panhard bushings after work one day. Then the trailing arm bushings. These really firmed up the rear especially while shifting ( I have an m46 trans).

*[Another note to hopefully aid someone in the future is the installation of the trailing arm bushings: I secured a large hose clamp around the bushing to keep the bushing from "spreading out" while pressing it in. While installing the first side I didn't do this and the bushing "opened up" and you could see the rubber separating]*

But definitely the biggest difference was when I replaced the torque arm bushings. Changing these out made the car drive the way I remember when I first bought the car about 10 years ago. I had a vibration in the steering wheel, my seat, and my feet at most speeds. It started as intermittent and progressed to a mainly constant vibration. Braking was the worst and it felt like severely warped rotors. I forgot how well these cars stop.

My inspection skills may not be the best but the bushings didn't look too bad. The smaller bushings definitely looked worse after removal of the torque rods and the larger ones were deformed. But visually I would have thought the large ones were fine.

Hi gsellstr: that's a great tip, thank you for adding.
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Old 02-10-2019, 09:23 PM   #7
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Absolutely! I've done enough installs of the poly torque rod bushings in the 7/9's, launched enough of them, fully greased, across the shop to need a better way. lol

I will say, new vs. old rubber makes a big difference on those, but the poly in that location alone is such an improvement with no real NVH issues. The poly is a full round bushing, so there's no gaps between bushing and the torque rod. It really tightens up the feeling of the rear end a lot. Even that roll-back on a hill when you set the e-brake, put it in park, and let your foot off the brake is reduced a lot.
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Old 02-12-2019, 05:52 PM   #8
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Thanks OP and others for the additional comments. Mine is an automatic so perhaps that explains less pronounced symptoms. However, I have had some speed dependent vibrations over the years that I have addressed with tire balancing a few times but the car seems especially sensitive to perfect wheel balance so I have suspected it may need more help.

I have had a set of these sitting on the shelf for a long time, sounds like maybe this will be the year they should go in.
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Old 03-06-2019, 10:33 AM   #9
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Default A Question About Torque Rod(s) Articulation

Hey everyone,

I have a question I hope someone may be able to answer:

Suppose the axle side of the torque arm(s) is unbolted and the subframe side is torqued to spec. Will the torque arm now be able to pivot freely where it's bolted to the subframe?
Or, in general, how much articulation should the torque arms have?

I'm asking because after re-installing the bushings for the upper torque rod I have vibrations again. After some fiddling around i unbolted the axle side and the torque arm stays in place and will only pivot in the subframe with a lot of persuasion, and not very far.

Sorry if this needs any clarification, I'm about to leave for work and not fully awake yet. I'm kicking myself for messing with the car after it was perfect.

Thanks for any info on what's going on here.
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Old 03-06-2019, 11:32 AM   #10
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With poly in there, the torque rods should be able to pivot. They may have some resistance but it shouldn't be significant. You should be able to move them by hand.
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Old 03-06-2019, 11:46 PM   #11
moustacio
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Hey thank you gsellstr, much appreciated.

I was only able to pivot the arm maybe 10 degrees or so and it went back to its original angle when I let it go. I don't know if it makes a difference but I have rubber bushings installed.

Since I'm never afraid to ask a dumb question: I'm assuming the torque arms pivot on the bolts going through the bushings yeah?

Thanks again, I'll hopefully be back to a smooth ride after the weekend.
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Old 03-07-2019, 12:04 AM   #12
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Oh, crap, nevermind what I said. My brain was stuck in the poly bushing world. With rubber installed, you won't get a lot of movement whatsoever, so the 10* or so, that's reasonable. Also make sure with rubber that you leave them loose until the car is sitting on it's own weight, then tighten the bushings, so you don't stress them.
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Old 03-07-2019, 09:05 PM   #13
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Thank you much gsellstr
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Old 03-08-2019, 05:51 PM   #14
moustacio
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Working from home today and had some time to check the car a bit. With the rear tires safely off the ground I turned the wheels pretty quickly each way and saw nothing unusual happening with the Driveshat, axle, or the rear suspension bits. I took out both toque arms and the bushings appeared fine. Then with the car fully on the ground I tightened the arms to 104ft/lbs.

I have a few questions about driveline angle if you all don't mind.

I can start a new thread about this if that is more appropriate. Where should I check on the differential housing to get the pinion angle without having to unbolt the driveshaft back there?

I have a 1031. Measuring near the back of the housing I get a different angle than the front of the housing. I'm going to try and rig something up to get that angle off of the ujoint but it would be nice to measure off the housing if possible.

Another hair brained idea I thought of: would it help at all to rotate the large oblong bushings for the torque rod 90* to help with vibrations?

Sorry for the hassle but I appreciate any help, thank you
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