Clunk: Time to Replace C/V Joints?
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I had enough trouble with two bolts... can't imagine 4 unless those are self-tapping bolts. I'm also glad my car is a lefty - It would be impossible to get my hands in there under the dash with a steering column, pedal box, pedals and master cylinders to get in the way.
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That bracket sure is pretty. I had enough trouble with two bolts... can't imagine 4 unless those are self-tapping bolts. I'm also glad my car is a lefty - It would be impossible to get my hands in there under the dash with a steering column, pedal box, pedals and master cylinders to get in the way.
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"Hang on a minute lads....I've got a great idea."
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My Mini had the exact same problem when I got it. The sound I was hearing was the subframe extension under the right footwell oil-canning the floor pan each time power came on/off. It took me a while to find the cause too. The factory bracket had been brazed on again at some point in the car's past but that too had failed - apparently brazing doesn't stick to painted metal very well! I made a basic bracket from angle iron bolted through the cross-member. It was a challenge doing that by myself!
What I also found was that, since the small bracket was loose, the thrust of the dogbone was taken up entirely by the hole in the plate sitting under your master cylinders ( I have hoses there). The hole had been completely torn out with metal fatigue.
I made a replacement plate out of 1/4" aluminum checker plate, which can be seen in the pic attached. Below it you can also see the remnants of the original lower bracket with the clutch pipe fitting still attached. It is held securely by the angle iron bracket. I didn't want to mess with the clutch hydraulics until I needed to.
I think that part is available at Se7en.
If in doubt, flat out. Colin Mc Rae MBE 1968-2007.
Give a car more power and it goes faster on the straights,
make a car lighter and it's faster everywhere. Colin Chapman.
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My Mini had the exact same problem when I got it. The sound I was hearing was the subframe extension under the right footwell oil-canning the floor pan each time power came on/off. It took me a while to find the cause too. The factory bracket had been brazed on again at some point in the car's past but that too had failed - apparently brazing doesn't stick to painted metal very well! I made a basic bracket from angle iron bolted through the cross-member. It was a challenge doing that by myself!
What I also found was that, since the small bracket was loose, the thrust of the dogbone was taken up entirely by the hole in the plate sitting under your master cylinders ( I have hoses there). The hole had been completely torn out with metal fatigue.
I made a replacement plate out of 1/4" aluminum checker plate, which can be seen in the pic attached. Below it you can also see the remnants of the original lower bracket with the clutch pipe fitting still attached. It is held securely by the angle iron bracket. I didn't want to mess with the clutch hydraulics until I needed to.
.
"Hang on a minute lads....I've got a great idea."
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Due to the amount of work getting to those areas on a late model Jap spec Mini the previous owner fitted an engine steady to the thermostat housing and bulkhead which seemed to work fine, not the best but worked for him in a pinch and might be a good addition for your car.
If in doubt, flat out. Colin Mc Rae MBE 1968-2007.
Give a car more power and it goes faster on the straights,
make a car lighter and it's faster everywhere. Colin Chapman.
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…but I would suspect that will need to be welded up in the end.
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After 6 months of scratching my head, I finally found the source of my “clunk.” I initially described it as sounding and feeling like a broken motor mount and/or slack engine steady. I checked my motor mounts and engine steadies and gave the valve cover a cursory tug and everything seemed solid.
I jacked the front wheels off the ground and was concerned with the slack in what seemed to be the diff and/or pot joints—rotating the wheels by hand seemed to produce the same clunk sound. My mechanic and several forum members looked at my video and thought the play was within normal limits. Several members thought it might be that my steering rack was giving out. For good measure I replaced my ball joints, tie rod bushings, track rod ends, and front wheel bearings. The clunk remained. I was about to order a new steering rack.
I adjusted my valves the other day, and while rocking the car back and forth to cycle the valve train, I noticed the motor was moving way too much. Although the top engine steady was plenty tight, I could see the weld that fastens the clutch master cylinder support and also terminates the engine steady at the bulkhead had broken and was pulling away from the bulkhead as I rocked the car.
Lengthening the engine steady so that it is tight against the bulkhead solved the problem. Clunk gone. I’ll keep an eye on it, but I think we’re good.
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Check the steering arm bolts and locktabs on the hub.
There is also something not right with either the balljoints or the wheel bearing or both - there should be zero movement at 12/6 but you can clearly see the wheel & hub moving in the plane at 1:05.
Just because it's a new bearing doesn't mean that the hub is any good. I've given up on hubs that have had the bearing changed more than once or twice as they just go baggy and the centre step changes size. Did you check the spacer dimension against you hub or just install it on faith ?
The rotational movement and associated clunking seems pretty normal, but that doesn't mean that there isn't an issue, just not one we can diagnose instantly via the interweb. There's no substitute for being hands-on. Sounds to me more like the LSD engaging.
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Have you tried someone moving the steering wheel while you are under the car observing ?
I haven't been under the car while the steering wheel is turned. I'll try that next. Several people seem pretty sure my "clunk" is related to the steering rack. Observing it from underneath should put that issue to rest (or not).
Looseness you are demostrating will be a steering rack, tie rod or maybe a wheel bearing/hub issue.
If in doubt, flat out. Colin Mc Rae MBE 1968-2007.
Give a car more power and it goes faster on the straights,
make a car lighter and it's faster everywhere. Colin Chapman.
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I drive the car with a great deal of "mechanical sympathy." I'm careful not to bury the throttle nor immediately back off the throttle until the drivetrain slack has had a chance to catch up. Still, just coasting, the gear slack causes the "clunk" to cycle back and forth as the drivetrain loads and unloads. I'm pretty sure I've had this issue since new. It's taken me this long to eliminate all of the easy fixes; motor mounts, engine steadies, tie rod bushings, wheel bearings, ball joints, etc. I'm pretty sure the diff is the culprit. So, based on the video… excessive or not, that is the question.
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Have you tried someone moving the steering wheel while you are under the car observing ?
I haven't been under the car while the steering wheel is turned. I'll try that next. Several people seem pretty sure my "clunk" is related to the steering rack. Observing it from underneath should put that issue to rest (or not).
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When you shimmed your ball joints, did you do them dry and with the preload springs removed from the lower joints?
The rotational clacking I hear sounds like more like gear slack take-up: if you were doing it against the engine, you'd experience all the gear slack from the diff, the transmission (varying, depending on which gear was selected) and the drop gears. By the way the wheel appears to turn a little bit further after the clacking stops, It appears to me that the opposite wheel is beginning to be turned as malsal suggests. Try it again with the opposite wheel on the ground or otherwise immobilized.
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"Hang on a minute lads....I've got a great idea."
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Have you tried someone moving the steering wheel while you are under the car observing ?
If in doubt, flat out. Colin Mc Rae MBE 1968-2007.
Give a car more power and it goes faster on the straights,
make a car lighter and it's faster everywhere. Colin Chapman.
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1) The steering rack is fine. It's securely attached to the bulkhead and there's no slop in the rods.
2) Inboard & outboard CV joints are fine with virtually no play.
3) Ball joints and wheel bearings are fine.
That pretty much leave the diff as the culprit. I misspoke when I said I have a cross-pin diff. It's actually a Quaife LSD. With both front wheels off the ground‚ I can rotate the left & right wheels by hand and replacate the "clunk. So, my question is… is the amount of play in the diff within normal limits, or does it appear to be excessive? [video]
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If in doubt, flat out. Colin Mc Rae MBE 1968-2007.
Give a car more power and it goes faster on the straights,
make a car lighter and it's faster everywhere. Colin Chapman.
Total posts: 1368
Last post: Jul 20, 2023 Member since:Jul 15, 2008
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If it is the joints, should I suspect the inboard pots or the outboard joints? Thanks!
The play you have in the video around 1 min 7 seconds looks like the Nylon inner shaft bushing in the steering rack is worn out or displaced. Remove the front wheel and have someone turn the steering wheel back and forth slightly you should see the left side (if RHD) steering rack arm move up and down if it is worn, you can also grab it yourself and see the play.
If in doubt, flat out. Colin Mc Rae MBE 1968-2007.
Give a car more power and it goes faster on the straights,
make a car lighter and it's faster everywhere. Colin Chapman.
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