P38 D auto, brake fluid leak

Hello again peoples
I've searched the forum for the answer but come up short.. (If you knew me that would be funny as I'm short!). Anywhooo, the new 38 has an abs fault which I firstly assumed would be electrical, having had a quick look around the car I noticed that the OSF wheel and tyre was covered in brake fluid, so I popped the wheel off to have a quick look. I was expecting to see a split hose but all looks ok, once the wheel was off I could see that there was actually quite a lot of fluid, the hub and calliper was covered and there was a hanging drip off of the lower balljoint thread! I propped my phone underneath in video mode and turned on the ignition and waited for the abs pump to stop running, then pumped the brakes several times, my hope was to video where it was leaking from..... NOTHING! Not a drop was seen leaking from anywhere! The rubber hose look ok, popped off the calliper as this was wet to check the piston seals and all look ok, so where the heck is the fluid leaking from?!!! The pads have fluid contamination so I'll rebuild or replace the calliper as a matter of course anyway and the same for the hose but I'm stumped. Hope to investigate more this evening. Any thoughts?

If you are going to be looking at brakes have a look at the rear lines especially over the rear cross member if they have not been replaced then now is the time to do them

brianp38dse said:

If you are going to be looking at brakes have a look at the rear lines especially over the rear cross member if they have not been replaced then now is the time to do them

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OH! Thanks Brian, will do...

Is there a leak around the pump, master cylinder or pressure vessel ? Any of these could put fluid onto the OSF wheel ?

Pull the OSF arch liner. There two joins in the pipe to the rear in there, although these are unlikely to be the source of the fluid in your case.

Rallymantony said:

OH! Thanks Brian, will do...

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If they are bad you replace them from a union in the drivers wheel arch all the way to the back, i have done mine and another members if you need help give me a shout your not far down the road, and if i can get it working again i have diag for p38

brianp38dse said:

If they are bad you replace them from a union in the drivers wheel arch all the way to the back, i have done mine and another members if you need help give me a shout your not far down the road, and if i can get it working again i have diag for p38

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Thank you Brian, really very much appreciated.

pwood999 said:

Is there a leak around the pump, master cylinder or pressure vessel ? Any of these could put fluid onto the OSF wheel ?

Pull the OSF arch liner. There two joins in the pipe to the rear in there, although these are unlikely to be the source of the fluid in your case.

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Thank you pewood, I looked around the master cylinder etc and didn't see anything, however, there was a very small amount (and I mean small amount) of fluid sitting on the mount of the abs pump closest to the coolant bottle, the bodywork around it was dry so not sure what that's about, can't see any leakage from the abs pump either, someone has tried to sort an abs issue before as I found a spare pump and two pressure vessels (not sure if that's the right name) in the boot, all look second hand by the way.
I'll pull the arch cover off and take look.
Thanks so much for taking the time guys, it really is very much appreciated.

And one of these Open Ratchet Ring spanners make job much easier !!

pwood999 said:

And one of these Open Ratchet Ring spanners make job much easier !!

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I like that, typically I only have a 10mm and 12mm brake pipe spanner! Off the shops I go

Be careful you let the master cylinder drain as the system can be a pain to bleed and it has to be done to a set procedure

The brake peddle switch can throw up an abs fault , it is a two way switch and needs the peddle pushing down whilst down pull the plunger out then let the peddle up

brianp38dse said:

The brake peddle switch can throw up an abs fault , it is a two way switch and needs the peddle pushing down whilst down pull the plunger out then let the peddle up

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Thanks Brian.
So I've pulled the inner arch cover off and all is dry, however, before I packed up last night, I cleaned the whole area with brake cleaner and placed paper towel on the floor, the theory being that I may be able to see if the fluid is dripping from anywhere else...... All is dry!! The hose, the calliper everything! Not a drop fluid anywhere.... I sat there pumping the brakes (with ignition off as I have the battery off at the moment) and no fluid leaked. The inner arch was only held on with one fixing and preyer so someone has been under there recently I would wager.... Think I'm going to top up the fluid, fit new pads, bleed as per the advice on here and then se what happens.. I'll also check the pedal Brian, thanks for the tip.

The fluid level should be checked with system running, it will read high if the motor has been sat over night and will drop to correct once pump has stopped.

My guess is caliper. Maybe slip some tissue paper under the pads and then stamp on the brakes for a bit and see if the pistons weep.

Grrrrrr said:

My guess is caliper. Maybe slip some tissue paper under the pads and then stamp on the brakes for a bit and see if the pistons weep.

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Good idea Grrrrr, I'll try that this afternoon.

Iv come across this ,the outer seal you can see is the piston dust cover ,if you lift it gently off the piston center and theirs fluid under it ,the main seal or seals ,there's two pistons, is failing ,usually because of corrosion on the piston

dubbleRR said:

Iv come across this ,the outer seal you can see is the piston dust cover ,if you lift it gently off the piston center and theirs fluid under it ,the main seal or seals ,there's two pistons, is failing ,usually because of corrosion on the piston

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And that is the exact problem I have dubbleRR. Spent a little time on it this morning (couldn't sleep) and that investigated the calliper properly.
So this evening I fitted a spare used calliper and bled as per the instructions, I will be replacing both front callipers for new ones but I wouid like to get her to an MOTable stage first and make sure everything works before putting new shiny bits on. But as I was saying, I fitted another calliper on and bleed, still has the abs light on the dash so that's one thing I can rule out.
I had a look at the brake peddle like Brian suggested, I was running out of time by this stage so haven't had a proper look but I'm not 100% sure what you mean Brian? I'm working tomorrow but should be able to spend a couple of hours on her in the afternoon.
Thanks for all the help peoples.

The plunger that the pedal operates needs pulling out with the pedal held down so as the pedal comes up it sets the distance
it may not be your problem but its free and quick to do and rules that out.

No telling ye how to suck eggs ,But the cars got to move at 5+ mph for the light to go off ,if you know that then try pushing all abs sensors all the way home in there sleeves they self adjust when moving ,,a bad wheel bearing can knock them out of sorts ,if all that fails then check each sensor for continuity with an ohms tester ,about 1.5 ohms is good .open circuit its kaput.....

brianp38dse said:

The plunger that the pedal operates needs pulling out with the pedal held down so as the pedal comes up it sets the distance
it may not be your problem but its free and quick to do and rules that out.

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Brianp38.... I don't know who you are or what you look like... But should we ever meet, I'm going to kiss you!! Or maybe I'll just buy you a beer... Pulled the brake switch off and cleaned it up, pulled the plunger and refitted as you suggested... No more ABS light . Drove the car around the compound and seems all good other then when you stamp on the brakes hard ish, the abs plus the red brake light next to flashes up, it is just a flash though.
Thank you everyone for taking the time and for your help.
One problem solved (for the moment), many to go......
EAS next, going to either download the software (if I can find it for MAC) or order a magic box of tricks.