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jackleberryfin

Subframe Crush tube inner diameter too large **Problem**

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I have what feels to be quite a unique problem.

 

I bought a US master PU bushing KIT. I also bought the Subframe PU bushings.

 

After installing all the rear control arm bushings without a hitch i went on and did the subframe.

 

Install went fine, very easy in fact. heated and pushed them out.

 

My problem is that ever since doing the subframe bushings my car has been making a massive clunking sound. similar to the diff backlash people always complain about.The clunk occurs when quick change of gears is made or during take off. Generally when ever the clutch is engaged quickly. In addition when there is a large difference between speed and current gear. (I.e im in 5/6 gear and going 70. i hear a grinding.... speeding up to 90/100 and the grinding goes away.)

 

a couple of months have gone by now and ive thought about it from every angle i can. Diff was fine before the bushings went in very quite. I had the rear bearings replaced which were shot.

 

the clunking sound is still there. Finally i thought what if the subframe crush tubes were too large of a diameter and the entire subframe was moving a few mm when shifting. what i have come to assume is that my subframe moving back and forth is causing my propeller shaft to punch my transmission. And that the grinding is quick small punches making it sound like a grind.

 

I checked the manual that came with the set and the inside diameter is 21.793mm .immideiately i went and searched for another manufacturer who supply a kit with such measurements. Nolothane have their part listing INSIDE DIAMETER :21.2mm.

 

Okay so i went and had a part custom made to suit my new Inside diameter. took off my subframe today and tested the new crush tubes on the subframe chassis Bolts..... and they still have a fair bit of play. The bolts seem to be closer to 20mm. Ive noticed some scuff mark on the bolts on the front and back in the direction of travel (some of the paint has been taken off) which seems to indicate there is some movement there.

 

what i would like is to see if anyone on here has some authority on whether the crush tubes for subframe bushings are supposed to have any play and or the inside diameter of the OEM Crushtube.

 

I am such an idiot. i was in a mad rush at the end of the job and didnt check the fitment. and also binned the old OEM bushings i took out.

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Edited by jackleberryfin

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The subframe bushes are definitely a loose fit on the studs. The subframe relies on the nuts being tightened to stop it moving, rather than a tight tolerance on the studs.

 

If you have put solid or poly bushes in, more diff noise being transferred is normal.

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Thanks for the reply.

The workshop manual says its 98-118 Nm of torque. which is where i had it. I dont want to overtighten them and pop a stud.

Maybe people do them up tighter? any ideas on the inside Diameter of the OEM Crush Tube?

 

It does seem like excessive movement not just noise transfer. Was really hoping it was a tolerance issue.

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Pretty sure nothing is wrong and it's just the noise transfer.

I've got a solid transmission mount and all the clunks, bangs and whirs are about 10 times louder.

Don't stress out.

Put the stock ones back in if it's an issue.

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