What's this thunk?

[cmohr]

Glen I have heard of a few lads saying their rear handbrake linings have delaminated and come off the shoe, and if you suspect a caliper, they could also be a binding point, Simple to pull of a rear disc and see.

[glend]

Making some progress with trying to pin down the 'thunk'. Did a test today: drive along at 50kmph, get on the brakes hard, then accelerate, then on the brakes etc. I managed to get a cycling thunk going doing this. When coasting downhill in neutral at 50kph and doing the same thing (except the acceleration bit, using downhill momentum and just let off the brakes then on again, etc) no 'thunk'. I did another test on a flat road at 60kmph, backing off the throttle and then getting on it again (no brakes) doing this over and over sets up a thunk on power on (hard to hear/feel at that speed but it is there). This says to me that it is probably not brake related but more likely driveline related. If driveline related it narrows it down to the transfer case, slip yoke and the drive shaft Uni. I've already pulled the shaft once (after the Desert Trip when a thunk interpreted to be the lack of slip yoke grease first appeared/ and before Jambo) when I regreased the slip yoke, so I am sort of leaning towards the transfer case output bearing or the drive shaft uni (top one).

If this is the problem I know where to place the blame - the Birdsville Track last winter, where the convoy was travelling at what I regarded as too fast for conditions and had to brake hard for floodways/washouts/standing water/etc and then accelerate back to speed. Slamming into dips, floodways etc on a highly corrugated track in power off and power on situation stressed the driveline to the point that on rebound coming out of the bottom of these gullies the 3" lift was putting alot of angle stress on the driveline which may have done a job on the Uni and output bearing.

Maybe this is the justification I have been seeking for putting in the double cardan joint driveshaft.

Comments? Does it sound correct (the reasoning)?

[glend]

Has another crawl around underneath today. Noticed that the Old Man Emu rear shock (NS132) lower bolts are almost sitting on the metal of the shock eye on the passenger side (driver side is not much better). So if the shock bushings have gone could that be the source of my noise? Can I change just those lower shock bushings or should this be a sign to replace the OME shocks? If I can just change the bushes where can I get them (rubber or something else)?

[Auberon]

Sounds like your making progress. Good stuff. This is the "sort of" noise the front LCA bushes (clevis bracket) make when they are on the way out. Backs up your suspicions of the noise being in the rear.
These bushings shud be pretty standard sizes.
If you measure up and look at the Redranger site or some of the other Aussie ones you can search on the basis of style size and type. Just entering Nolathane will bring it up in a std search and anyone who stocks them shud be able to get them.
As a last resort:
Even getting close in nolathane (slightly oversize) these can be easily machined to size - machining might be an issue over Christmas shutdown tho. BUT if you have any luck and do need machining put out a holler in this thread - some of us have lathes etc.
A good parts enterpreter might be able to help. Do you have a regular? The blokes I have been going to for years never just look blankly at me when I ask about the Jeep - I've sent so much business their way they wouldn't ever just say no and pee me off.

BTW IMHO it doesn't necessarily mean the shock is gone unless leaking etc. or if you give it a jounce test how many bobs to settle? - traditional but very effective.
Cheers
Auberon

[JEEPaul]

Does it do it in 4wd? Prior to greasing my slip yoke in both the xj and kj I strangely noticed the thunk didn't occur when in (full time) 4wd..

[cmohr]

Ahhhh. I had this clunk from the shocks. Mine came from the top mount, the crush tube was not quite big enough, so even when the bolt was as tight as possible the shock could still move up and down and rattle on the bolt. I had to add an extra washer in between to add the extra tenson to make the bolt lock up enough and stop the clunk I had. I would only get it on bumps, not any other time. You should be able to get new bushing if they are worn, maybe contact Stu???

[glend]

Cmohr thanks for the tip on the top mount washer, I'll have a look at them when I pull the shocks out.

I've talked to Stu but I decided to go ahead and order in some new OME 132s from JBA (great price and exchange rate at the moment). My old ones (despite having less than 40,000kms on them) are rock blasted, pitted, rusted, and dented from my trips over the last couple of years so I will just replace them now and rebush and repaint the old ones for spares for the Cape Trip (or maybe run the old ones as the primaries on the Cape Trip and then throw them away). I still have Palla's original equipment crd front struts in the shed as spares for my struts (his have less than 20,000kms on them), so the fronts are backed up. I know the clevis buses will need replacement soon and I already have the spare bushes for that job. Once I get the new OMEs in I'll re-run my tests to see if there is any remaining noises.