Thread: Brake Pulse/Pad Knock back-Defender

Loose caliper retaining bolts? Bent stub axle?

Hey Big Jon - will check the caliper bolts tonight - both stub axles are new.

Originally Posted by dhumphri

Hey Big Jon - will check the caliper bolts tonight - both stub axles are new.

If the stub axles are new, I don't suppose there is any possibility that one is loose?

Another possible cause could be oil or brake fluid on part of one disc, but this doesn't explain it being worse on right hand turns.

Another thought occurs to me - you don't by any chance have the centre diff locked do you?
John

Now what are you doing with your foot on the brake on high speed corners???

Does the pedal respond to a pump? Pump it up & stop in a straight line - how does that compare to pumping it, turning into said corner, & then stopping in a straight line?

Two things come to mind with this

1. I had to take my disco back after service once, brakes were terrible. Transpired that the bearing was sitting on a lip. Tight, but not fully home. Seat it properly & all was well.

2. My MG has 4 wheel dunlop disc brakes. Brake Pedal has always been inconsistent. Must have checked the wheel bearings 1000 times looking for pad knock off. The answer was axle float in the rear. Its just a 1959 design thing I've got to live with.

Regards
Max P

<snip>The answer was axle float in the rear. Its just a 1959 design thing I've got to live with.

ahh, the joys of a semi-floating rear axle and an opposed piston caliper.
This is where a slider caliper has it over an opposed piston caliper. The slider just floats back and forth with the wandering axle.

If you have replaced the stub axles and the bearings recently then check that the bearings are correctly positioned and loaded up...jack up each wheel and see if you get any movement when you rock the wheel backward and forward at 90 degrees to the horizontal.

how do you know your discs are not warped....?
have you checked them since the pad knock back started....?

Following work has been done/item checked:

1. Graeme Coopers recently replaced both stub axles/bearings due to bearing play on both front wheels - have double checked and there is no bearing play at all (the stub axles were worn by offset rims).
2. There are no fluid leaks near disks/pads.
3. Coopers also replaced front d/s swivel bearings and checked adjustment of pax side also.
4. The car has a brand new steering damper on it.
5. Can find no play in front end at all.
6. When I said braking into high speed corner I mean very light application - this is where the pulsing/knock back is felt most.
7. The brake pedal itself is solid and booster checked out OK by Coopers.
8. Front disks and pads were brand new maybe 3-4 months ago.
9. Rear disks and pads also new 3-4 months ago.
10. More for information the front diff was dissassembled last month for new pinion and carrier bearings.