Braking Bad...

Doo · Dec 14, 2016

Play on words, but reasonable question.

Yesterday, my mate fitted all new pads front & rear (on the box it said Punto & BMW).

I didn't fit new discs yet as A) it's winter and B) they still have a bit of life left despite the slight lip.

Now my old girl has 2 pot front calipers which are in good condition with nothing found to be wanting & nothing seized or partially sticking, yet the brakes feel heavy to push. My sister commented on this as she drives an L322 supercharged. I assume they would have 4 pot calipers.

So imagine my surprise when looking online I found four pot calipers for the P38???

Next year, I plan on fitting new discs & pads around summer time, so would it be a reasonable desire to fit these upgraded 4 pot jobbies or are they for certain flavours of P38? For instance, would I need different discs? Would the pads I just fitted be the same or completely different?

I know the calipers fitted now also fit the Disco 2....

Thanks all

Lone_Wolf · Dec 14, 2016

I'd expect the brakes would feel quite "wooden" until they have bedded in properly. You need to give them at least 200 miles of gentle breaking in before they are back to normal. I fitted new discs and pads in the summer and they took a fair while to feel right again.

Doo · Dec 14, 2016

Lone_Wolf said:
I'd expect the brakes would feel quite "wooden" until they have bedded in properly. You need to give them at least 200 miles of gentle breaking in before they are back to normal. I fitted new discs and pads in the summer and they took a fair while to feel right again.

I realise that as I work on brakes all the time.

Sorry, I should have been clearer, my brakes have always felt heavy and it doesn't bother me in the slightest.

Wife commented as she took the car to work today and txt me saying it felt heavy. I told her it's fine, they are still bedding in.

But I recalled my sister driving my car for the 1st time saying OMG the brakes are so heavy!! I drove her RR and with it being super charged I suspect the brakes are four pot, which would explain why they are so much better.

I want better brakes, are they available

Lone_Wolf · Dec 14, 2016

I have not seen any caliper upgrades specifically for the P38. If the whole braking system on a P38 is in good order it's absolutely up to the job and IMHO does not feel heavy by any means.
When I did my brakes in the summer I replaced all the discs, pads, all the flex lines, all the caliper pistons and seals. Brakes are great and not heavy.

Doo · Dec 14, 2016

Trying to remember now, does my car have the Citroen sphere to assist the braking or is it the good old frying pan and pipe to the manifold

Need to check it out, could be a fault there. Thanks to Michael Scott from Barry 4x4 in Mid Glamorgan for the suggestion

Doo · Dec 14, 2016

Lone_Wolf said:
I have not seen any caliper upgrades specifically for the P38. If the whole braking system on a P38 is in good order it's absolutely up to the job and IMHO does not feel heavy by any means.
When I did my brakes in the summer I replaced all the discs, pads, all the flex lines, all the caliper pistons and seals. Brakes are great and not heavy.

Personally, I feel ok with the brakes. They pull up well enough and no deviation under heavy braking. It's just others saying they feel really heavy. To me they are heavy, but then she's a big girl and needs a firm push on the stopping pedal.. We'll see. I'll check out if the vacuum is a problem.

Lone_Wolf · Dec 14, 2016

As far as I can tell all P38's have the same braking system and yes it does have an accumulator for storing hydraulic pressure. It's right on top of the brake pump.

Doo · Dec 14, 2016

Lone_Wolf said:
As far as I can tell all P38's have the same braking system and yes it does have an accumulator for storing hydraulic pressure. It's right on top of the brake pump.

With the extent of my injuries I haven't been under the bonnet in a while, but I do seem to recall seeing an accumulator somewhere in there. Perhaps it's losing it's mojo

Ahh well, easy fix. I made a tool for removing them from underneath Citroen's, so it should fit in there and the bonus is no jacking up and laying on the cold hard ground

brianp38dse · Dec 14, 2016

You can test the sphere if all is good the brake pump should run after every sixth pedal push iirc, if less the sphere is not holding pressure.
and as you say easier to change than a Citroen`s, I remember the Bx system well

Doo · Dec 14, 2016

brianp38dse said:
You can test the sphere if all is good the brake pump should run after every sixth pedal push iirc, if less the sphere is not holding pressure.
and as you say easier to change than a Citroen`s, I remember the Bx system well

I sometimes hear the pump when I switch on the ignition. It doesn't go that often, but then I guess it doesn't have to... I clearly don't hear it for the stereo

Tomorrow, I have the orthopedic dept to attend so I may spend a moment faffing with the bonnet open and poking the brake pedal with my crutch

martyuk · Dec 15, 2016

The ABS pump should (on average) run for about 45 seconds on startup (with the ignition in position II) to charge the brake system and accumulator. If the pump runs for a really short period of time on startup, and then every time the brake pedal is pushed, then the accumulator is shot, as no pressure is being stored - so the pump has to kick in all the time to provide the braking pressure.

On a good system 3-4 presses of the brake pedal is about right before the ABS pump will come on again. If the pressure is dropping really low, then when you jab your foot on the brake pedal quickly, the 3 amigos will flash on briefly until the pump brings it back up to pressure aswell (had that on my first one - which again was a sign of the accumulator needing replacement).

Also - I've never heard of 4 pot brakes on a P38... unless it was a custom thing on an overfinch or something like that...

Hope this helps,
Marty

Grrrrrr · Dec 15, 2016

2 pot on mine.

And my brakes aren't heavy at all. They're fantastic. Summat ain't right!

Braking Bad...

Doo

Well-Known Member

Lone_Wolf

Active Member

Doo

Well-Known Member

Lone_Wolf

Active Member

Doo

Well-Known Member

Doo

Well-Known Member

Lone_Wolf

Active Member

Doo

Well-Known Member

brianp38dse

Well-Known Member

Doo

Well-Known Member

martyuk

Well-Known Member

Grrrrrr

Technician, Bodgit & Scarper Ltd

Similar threads