Thread: P38a to rr sport

G'day Camo

If it has a Vaccum hose don't discount the fact that the hose may be porous and letting vac out.

cheers

Thats what I hoped.. but had that checked.. no leaks at all in the booster

Originally Posted by Camo

Had accumulator checked.. nothing wrong with that

but what do you think about this for a reason the brake place told me

he reckons the disks might need machining if they a flogged.. basically if they are warped they will open up the caliper a bit making the first brake push spongy..

can't hurt to try yeah?

Camo

I had the discs on my P38 machined and new pads fitted last week. If there is any warp in the discs you will notice the shudder before you notice the spongy pedal. As a test take it for a run on the freeway at speed. Gently apply brake pressure - you will instantly feel if there is any disc warp.

Its not expensive though, so if there's any doubt just get it done.

Dave

I had the discs on my P38 machined and new pads fitted last week. If there is any warp in the discs you will notice the shudder before you notice the spongy pedal. As a test take it for a run on the freeway at speed. Gently apply brake pressure - you will instantly feel if there is any disc warp.

Its not expensive though, so if there's any doubt just get it done.

Dave

there is a tiny amount of warp in the disks..will get it done anyways

never heard of this before but worth a try

main concern was when I towed my mates Defender on a trailer and isn't too exciting when you have to pump a couple of times to get the brakes to work
Just suprised how much effort it is to find a prob like this

Camo

What an Awesome transformation It would be at least half the price of the real thing and looks just as good

Brilliant

Originally Posted by UncleHo

If it has a Vaccum hose don't discount the fact that the hose may be porous and letting vac out.

No vacuum booster on a P38A. They use an hydraulic pump to provide brake pressure. Any leak would be seen as a spray of fluid at 150 Bar!

re discs, yes, I've heard that a warped disc will push the pads back.

However, aftermarket replacements are pretty cheap (I replaced mine yesterday) so I doubt that it would be cost effective to machine them - especially if they are worn. If adm333 hadn't mentioned it, I would have said that P38A discs (from others I've spoken to) don't tend to warp.

I know you say the accumulator has been checked. Did you time how long it takes to get brake pressure from a cold start?

A P38A has pretty good brakes.

Ron

Brake pressure from start is quick and fine.. It only does it when driving for about 10mins or more without braking..you put foot on pedal and it goes down a bit further than usual and have to pump 1-2 times to get it back to normal.
Always gets me as I come off the highway ramp and have to slow down quickly..I always forget to pump it! Glad I'm not a tailgater

Camo

As P38a has said there is no vacuum system on a P38a.(other than the self contained system in the Cruise Control )
A few extra hints:
Two critical items are the pump and the accumulator.
As Ron has asked...measure the pump running time from cold start and post result.
My brakes have sometimes taken several attempts at pressure bleeding before loosing that initial spongieness after major work.
If the front wheel bearings are not adjusted correctly the rotor can 'open up' the disc pad positions and there will be no shudder on brake application.......however you would have other symptoms such as bump shudder, tramlining, noise etc and your ABS diagnostic would show a 'sensor' fault on the offending wheel.