Noise/vibration

[tack43]

I have a noise/vibation on my 1990 3.9 auto with BW transfer box. It sounds like I'm driving on one of those motorway rumble strips. It happens around 30mph quietly and between 60 & 70 mph loudly on light acceleration/constant speed but goes on overrun, brisker acceleration. I've checked all the usual suspects (wheel balance, play in moving parts etc) and substituted the front prop for a known good one. I can feel vibration though floor and accelerator pedal but not brake pedal or steering wheel. Seems to be coming from the front. It's gradually getting worse/louder. Any ideas anyone?

Cheers

[lambert]

Beyond prop joints I would suggest prop being phased correctly? Or gearbox t box but I don't know enough about the bw to comment.

[JIMBOBLY]

the borg warner transfer box has a chain,it may be that loose/stretched,or could be the bearing on the output flange for front prop

[Range Rover Blues]

Is it lifted or not?

Does it happen in all gears or is it worse in one particularly?

Did you drive it with the propshaft removed altogether?

Is it misfiring and have you checked for compression?

[tack43]

Thanks for the replys. prop should be in phase as it hasn't been moved and was ok prior to problem. bearing or chain sounds good for a potential problem - would it have play? is it usual for bearings to have a resonant speed?
It's fitted with H/D springs red/white rear and diesels (blue/green?) front with De Carbon shocks no ARB - so an inch or so I guess.
No haven't driven it without props
At 30 gear is 3rd, 60 4th. when accelerating vib goes so doesn't show in lower kickdown gear
compression in normal range no obvious misfire. running on gas so misfires normally obvious

[MuddyMike]

Could be the tyres, some suffer with what the trade calls "blocking" when the blocks of tread wear unevenly.Try stoking the tyre with your hand, can you feel uneven tread blocks. Only real test is swapping wheels.

Could also be front end of rear prop. Try removing it and going for a drive, remember to engage dif lock or you won't go anywhere!

Mike

[tack43]

Thanks. Tyres are ok. still need to check prop while removed.
" Engage diff lock" - Haven't got one it's a BW transfer box.

[James.Harwood]

Won't be the chain, they make a very harsh knocking noise when knackered, most obvious under hard acceleration.

[tack43]

Seems like the A frame bushes are shot. Have been noticing a bit of wobble on the back. Haven't been able to check properly as I'm using my axle stands on the rebuild. No doubt the A frame ball joint could do with renewing too! There's no play but the self leveler is pushing on the joint. Wonder if this could be causing the vibration as the diff nose looks lower than it should be and could be impacting on the rear prop. Another job for the New Year!

[Range Rover Blues]

COuld be a prop UJ, also check the handbrake isn't binding, though I thnk it unlikely it's an easy fix.

[tack43]

Changed the bushes but unable to get ball joint/self leveler off. May need to cut a hole in the floor to get at the top bolts. The leveler BJ's are shot - bottom is completely seized and top has loads of play.
Had a bit of death wobble - found play in track rod BJ and drop arm BJ. Changed but it's getting worse to the point I don't want to drive it and haven't got time to get under it - I'm at uni and have lots of achedemic s**t to do - will have to use the car for a bit. Will update when I can.

[Range Rover Blues]

I have a big problem with death wobble too.  I only get it on ABS cars so I think it's something to do with the top bush, unlike a non-ABS car you can't adjust the wear out of the bush pin.

As a quick "fix" you can set the front end toe-out a bit and fit stiff dampers.  Make sure all ball joints are good and nip up the steering box.

Also check the steering damper, ours is so bad it broke the steering damper bottom bracket.

Also check radius arm and panhard rod bushes.

[tack43]

Well seem to have got to the bottom of the vibration but don't understand why! It seemed to start when I fitted HD front springs. I've gone back to standard springs and the vibration has gone.  Steering damper was shot so replaced and no more death wobble.  Still got the A frame ball joint and leveler to sort out and that can only improve things even more.   

[Range Rover Blues]

Good news!

Has fitting the old springs changed the ride height AT ALL?  if they are the only things you swapped then it suggests a propshaft UJ still.

Also, could the springs have had any effect on the death wobble?  I'm asking because I still haven't cured ours.

[tack43]

Ride height has been reduced by about 1/2" - only noticeable on measuring. Prop is fine I took it of my other RRC which has a 2" lift and no vibration. Still need to adjust N/S swivel preload as it's a bit loose but the shot SD was not helping!
Got a new problem now. The brakes were fine when I parked it up in Feb but now it feels like it's got a warped disc - feed back on braking. It's got ABS and I changed the rear calipers in Jan - I used a pressure bleeder but wondering if air is in the system. I can't see a disc warping it's self sat on the drive!

[Range Rover Blues]

I've had that.  If the disks rust then they will judder, the surface gets ruined in the portion exposed to the air and doesn't rust between the pads.  Total pain becuase skimming them is the only real fix.

If you lay one up for a while it's worth pushing the pistons right back in so the whole disk surface can breath.

Using them just made them worse.

If I get chance this summer I'll put them in a 4-jaw and work, mine were EBC vented/grooved and cost a good few quid.

[tack43]

More work to do then. 

[tack43]

Got a new problem now. The brakes were fine when I parked it up in Feb but now it feels like it's got a warped disc - feed back on braking. It's got ABS and I changed the rear calipers in Jan - I used a pressure bleeder but wondering if air is in the system. I can't see a disc warping it's self sat on the drive!

Seems like it was a fractured break pipe! Fixed and now ok.