P38a brake wobble

Hi there,

In June I've changed right front wheel bearing due to pretty much f**ked condition. Tyres were balanced, runout of the tyres set.
After 500 miles car started to judder when braking, and I've thought - warped disc (had the same on my late Mondeo, exactly same feeling).
As it wasn't felt through the steering wheel i ordered rear pads and discs and changed them by the book with everything cleaned and torqued to factory values. Pads were Lucas, discs made by Ate, so no cheapo made by neighbor parts. The judder is still there, although a little different than before, now it feels like higher frequency and a little more through the steering wheel. The car seems to pull a little to the left when braking hard, i can also hear left front tyre squeal just before the ABS kicks in (which happens a little too early if i think of it now), feels like the car would twist the whole front end a little to the left.
And now, questions: I presume warped front disc would still feel through the steering wheel, but have no experience with it on live axles. Does it feel the same as on an usual car or less intense?
Front discs look OK, but haven't measured them for warp yet, i don't exactly know how to. Pads look ok too. :doh:

Thanks,
Crt

Worth a try
I had this on my last p38 put new pads and discs all round. problem gone! then some **** nicked it!

Front discs are warped change them.

Thanks, i thought so. I'll change front discs and pads. Hope that's all, it's getting expensive for my current status...

or front wheel bearings

jamesmartin said:

or front wheel bearings

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Think he said he has changed them or one of them James. Many people fit new pads to old discs and continue to use them harshly without any bedding in period. That is fatal for old discs that may have some grooving, until the pads bed in the high spots cause uneven heating and warp the discs.

Yep, i've changed right front wheel bearing and the left one doesn't seem too bad (no play in the wheel), so i hope there will be no surprises at that front. I'm changing front discs and pads this evening and report back.

Another question, how much free play in the rear axles is OK? I can currently turn each of the rear wheel (when lifted off the ground, of course) without any effort for about 3-5 cm measured at the tyre running surface. The other wheel does not turn at this point, neither does the differential output to propeller shaft. Oil in diff looked ok at last change, 5k km ago. The drivetrain clonk when going from forward to reverse drive is present and quite loud, i can hear/feel it also when changing gears or coasting and then accelerating in lower 3 gears (it's a manual diesel).

chort said:

Yep, i've changed right front wheel bearing and the left one doesn't seem too bad (no play in the wheel), so i hope there will be no surprises at that front. I'm changing front discs and pads this evening and report back.

Another question, how much free play in the rear axles is OK? I can currently turn each of the rear wheel (when lifted off the ground, of course) without any effort for about 3-5 cm measured at the tyre running surface. The other wheel does not turn at this point, neither does the differential output to propeller shaft. Oil in diff looked ok at last change, 5k km ago. The drivetrain clonk when going from forward to reverse drive is present and quite loud, i can hear/feel it also when changing gears or coasting and then accelerating in lower 3 gears (it's a manual diesel).

Click to expand...

The movement indicates play in the halfshaft splines and the planet wheels. Shows wear in the diff.

A little update. Changed left front disc and pads, everything ok. When i dismantled right caliper bracket i realised the rear pin is completely frozen solid by massive amounts of rust. It took me 3 hours with a blowtorch, 5kg hammer, a lot of rust remover spray, pretty large vice and whole assortiment of curses to get the fecker out. The head of the pin was a little bent afterwards, so i just drilled out first two threads and the pin is quite usable now.
I called the local garage, main dealer here in Slovenia and main dealer in Italy, which is 15 min drive from me... Guess what, nobody ever had slider pins in stock. Ever. They do not replace them when doing brake jobs. I wonder, do they even know the cars they're working on? Ordered some pins online, TOA in a week or two. Until then my bodge job should suffice.

Last update. Bought a lifetime supply tube of Bosch Superlube for disc brakes, 6€. Cleaned the unstuck pin with wire brush on a grinder, sanded with 150 sandpaper, lubed, reassembled everything.

First impressions:
- i was obviously running on backup circuit from last NY when i bought the car. Clicking in brake pedal and quite hard operation are thing of the past, now i almost fear that the brakes aren't working by the pedal feel.
- the thing finally drives as i've imagined a luxury off-roader should. No juddering, acceptable acceleration, soft (but still firm in a strange, pleasing way) brake pedal with loads of stopping power.

I'll still exchange all the pins when they arrive, just for the sake of new discs and all.

I am a very very happy camper right now. Until the next problem :hippie: