| Author | Message | ||
     Charlie J Unregistered guest Posted From: adsl-234-98-73.lft.bellsouth.net |
When first moving the car ('83 Corniche) the drive shaft makes a rubbing sound as though the bolts on the flange are rubbing on the frame. Worse in reverse. As the car is driven and put under acceleration the sound lessens till is stops after 3 to 5 miles. Could it be worn crossmember bushings and/or worn differential support bushings allowing the subframe crossmember to get out of alignment when at rest then under force to torque into proper alignment. (Message approved by david_gore) | ||
| bob uk Unregistered guest Posted From: brig-cache-4.server.ntli.net |
By drive shaft do you mean the one from the gearbox to the final drive or the ones (2) from the final drive to the rear wheels ? In any case put the car on the lift and using a bright light examine the shaft(s) for rub marks. If any are found apply chalk and road test and then see if the chalk marks have rubbed away. Also check the gearbox extension brg that is just in front of the front propshaft flange by seeing if the prop has any lift. The noise going as the car warms up could be a gearbox fault. Is the noise speed related that increases as speed rises regardless of what gear the car is in? Does the noise go when the car is coasting in neutral? (Message approved by david_gore) | ||
| Charlie J Unregistered guest Posted From: adsl-1-76-250.lft.bellsouth.net |
The noise is coming from the main driveshaft and sounds like it is under the tunnel at the rear of the front seat and the noise is} speed related. The tail of the gearbox has negligible lift and the noise does not stop when coasting. As far as the marking is concerned I cannot find any since the drive shaft is enclosed. The noise is worse at first when backing out of the garage and lessens when holding the brake and pressing the accelerater. (Message approved by david_gore) | ||
| Peter Colwell Experienced User Username: peter_colwell Post Number: 35 Registered: 3-2005 |
Whatever you do make sure that the source of the noise is certain, before undertaking expensive exploratory repairs. The fact that it is the same coasting and driving almost certainly rules out internal gearbox problems. I once had a big dealer mechanic, - not RR, - tell me that a front timing cover seal needed replacing, on an almost new engine, of a design that has been around for fifty years. But a few minutes check myself revealed a slight leak form the power steering return hose that had dripped on to the engine and then ended up at the cover seal. Ten seconds with a screwdriver fixed it.... | ||
| Mark Herbstreit Frequent User Username: mark_herbstreit Post Number: 62 Registered: 5-2005 |
As Peter says Charlie, start with the simplest explanation and work from there. The two rear engine mounts are adjustable and I would first loosen the bolts, use a trolley jack under the edge of the bell housing for support and lower the rear of the engine a little and retighten. (Scribe around the original bolt positions so things can be returned to the original position if necesary). As for the tail shaft being enclosed, have another look, it should be up in the tunnel somewhere!  | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 637 Registered: 9-2004 |
Worth checking the exhaust pipes mounts near where the pipes go through the body crossmember. They can hit the crossmember and give strange noises that can vary when reverse is selected. As the exhaust system heat up they can also vary position slightly. If the above is all ok i would look at the outer drive shaft[half shaft] UJ's, then the prop UJ's [hardy splicer]for excess wear [movment] Have you any vibration through different speeds then this would indicate wear in the drive shaft trunnions. (Message edited by pat lockyer on 03 January 2007) | ||
| bob uk Unregistered guest Posted From: brig-cache-4.server.ntli.net |
The propshaft is not enclosed. Check the front and rear propshaft universal joints. These should have grease nipples if not you may find liitle plugs which unscrew- screw the nipple in there. Any sign of rust comming out of a UJ is a sure sign that the joint is no good. Check front engine mounting by jacking on the sump pan with a thick piece of wood to protect the sump. This mounting gets containmenated with engine oil from the front crank seal. The rear engine mountings (2) are adjustable however unless they are loose or broken they will not go out of adjustment. If you found no lift in the gearbox rear bearing how could you not find the prop shaft? Note UJ when worn can be dangerous so you must check the UJs before yopu carry on driving. In Myth busters they dropped the front of a propshaft to see if the car would pole vault over the prop. It nearly did. The prop shaft tore the axle around and put the shaft through the boot floor and more or less wreaked the car. From personel experience I once saw a gear box rear extension ripped off a gearbox by a out of balance about to snap UJ ( Ford MkII Escort 1300) I remember this well because 6 months before I overhauled the engine and the owner tried to blame me because I should have seen that the propshaft was about to go wobbly. The batteries in my crystal ball must have been flat. (Message approved by david_gore) | ||
| Charlie J Unregistered guest Posted From: adsl-212-52-51.lft.bellsouth.net |
Sorry for not responding sooner but have been out of the country. I adjusted the rear motor mounts and the noise went away. Evidently the last person to adjust or perhaps replace the mounts did not tighten them enough so sound got worse with time. You guys were correct. Thanks again. (Message approved by david_gore) | ||
| Nigel Johnson New User Username: nigel_johnson Post Number: 4 Registered: 12-2008 |
bob uk,just doing the nearside outer UJ on Geoffs Corniche. You reminded me of a jouney to Hawkstone Park in the '70s in my mates dads Hillman Super Minx. Terrible droning from the propshaft UJ's. Scrambling was good though. Regards, Nigel. |
