Braking Bad
Posted: Mon Mar 16, 2015 7:40 pm
I had a problem last year with serious vibration under braking at a specific speed, around 45mph in my +2. Warped disks I thought, so had a look under the car, rear disks looked a little poor, fronts OK, but Oh Dear, CV boot perished on the drive shaft conversion. I considered doing the work & even got the bits, but poor weather and a lack of time forced the decision to take it to Spyder ? asked for new rear disks, pads, Handbrake pads & CV boots.
After a quick test, Andy agreed with diagnosis? Two days later, called up & Oh dear ? all work done, but vibration was the same. OK, I said see if you can track down the problem. Next phase is that Andy tried isolating each axle?s brakes to see which axle it happened on ? definitely rear. He inspected and replaced all bushes ? some wear but nothing he considered excessive. Still got the same problem.
Considered drive shunt ? replaced CV & prop joints. He tried skimming the drive shafts to see if there was anything out of line ? all fine. Are you keeping up? I went to visit & took the car for a test, with Andy ? still vibrating between 40-50. Tried swopping wheels around ? no. I tried left foot on the brake & right on the accelerator to maintain 45 with hard braking & the vibration remained. Creepy.
So what next? Diff was mentioned & as I had a spare (without back cover) we agreed that this would be fitted. Partial success, reduced vibration, but the (reconditioned ? huh) diff made a noise like a filling toilet at all speeds. Now we had to accept defeat as both Andy & Sean were more than a little concerned (as was I) at the mounting cost. Andy had never seen anything like it. Nearly six months & 3k miles down the road, the vibration is much less, but just perceptible. Noise of the diff has reduced, but I still am fed up with diff ?reconditioners? ? so far three done, one total failure ? seized up the rear end at speed (scary), one whiny and one sounding like a toilet filling.
This has been an expensive learning experience, and I wondered if anyone else has suffered from unexplained vibration under braking. Was it just an accumulation of lots of little bits of drive line flex coming together at a particular frequency? I don?t know, but I (and Andy) would like to hear if anyone else has suffered in a similar way.
At least all those bushes & joints are now replaced...
Jeremy
After a quick test, Andy agreed with diagnosis? Two days later, called up & Oh dear ? all work done, but vibration was the same. OK, I said see if you can track down the problem. Next phase is that Andy tried isolating each axle?s brakes to see which axle it happened on ? definitely rear. He inspected and replaced all bushes ? some wear but nothing he considered excessive. Still got the same problem.
Considered drive shunt ? replaced CV & prop joints. He tried skimming the drive shafts to see if there was anything out of line ? all fine. Are you keeping up? I went to visit & took the car for a test, with Andy ? still vibrating between 40-50. Tried swopping wheels around ? no. I tried left foot on the brake & right on the accelerator to maintain 45 with hard braking & the vibration remained. Creepy.
So what next? Diff was mentioned & as I had a spare (without back cover) we agreed that this would be fitted. Partial success, reduced vibration, but the (reconditioned ? huh) diff made a noise like a filling toilet at all speeds. Now we had to accept defeat as both Andy & Sean were more than a little concerned (as was I) at the mounting cost. Andy had never seen anything like it. Nearly six months & 3k miles down the road, the vibration is much less, but just perceptible. Noise of the diff has reduced, but I still am fed up with diff ?reconditioners? ? so far three done, one total failure ? seized up the rear end at speed (scary), one whiny and one sounding like a toilet filling.
This has been an expensive learning experience, and I wondered if anyone else has suffered from unexplained vibration under braking. Was it just an accumulation of lots of little bits of drive line flex coming together at a particular frequency? I don?t know, but I (and Andy) would like to hear if anyone else has suffered in a similar way.
At least all those bushes & joints are now replaced...
Jeremy