P38 clutch problems

This site contains affiliate links for which LandyZone may be compensated if you make a purchase.

JonYorks

New Member
Posts
10
Hello, new user to site and first post is a problem unfortunately.

We bought a P38 last month and all seemed fine until clutch pedal went to floor. Could bleed it and then would work fine until vehicle is parked overnight and then problem came back.
Have fitted new clutch master and slave. Seemed to bleed up successfully.
Now we have a working clutch until start the engine and then the clutch usually feels different and then goes to floor. If rebleed the system then normal opperation returns.
After trying several different ways of bleeding the air out I'm lost.

Dawned on me today that clutch operation is fine and no air in system until switch ignition on and the abs accumulator does its thing and this usually results in clutch problems again.

My main questions are:-
Is it possible that when the accumulator primes itself and draws brake fluid from the reservoir can it be sucking the fluid back out of the clutch system?
And the reservoir cap, is it supposed to be air tight or does it have a tiny hole? I have made a small hole with a pin to see if this stops the problem but won't know until tomorrow.
 
I know from searching that the usual thing to be told whenever anyone mentions a p38 clutch is that the rolls pins will have snapped and gearbox needs to come out etc.

If the roll pins break does this just allow the forks to rotate on the shaft?
Why if I bleed the system does my clutch work correctly?

I would like to be sure before I remove the gearbox because only have a barn and no lift so its going to be a hard job laid on back underneath :(
 
Thanks for that.
I was thinking the same too.

From searching on net I'm now 90% sure that the brake master cylinder cap should be vented, this one wasn't.
Hoping that the pin hole I made in the cap has fixed my problem but time will tell.
Doesn't explain why though that the clutch worked fine for 2 weeks because the same cap was fitted then too.
 
At first guess I would have suggested slave cylinder rather than anything with the brakes. Cheap to replace and even cheaper if you just want the kit with the seals.
 
When the clutch pedal go's to the floor with no resistance can you put the vehicle in gear with no drive, will the pedal lift on its own or do the gears crunch because the clutch isn't dis-engaging???
 
Last edited:
At first guess I would have suggested slave cylinder rather than anything with the brakes. Cheap to replace and even cheaper if you just want the kit with the seals.

Hi. Have fitted new slave and clutch master.
The clutch gets its fluid from the brake fluid res hence the query over brake fluid cap.
 
When the clutch pedal go's to the floor with no resistance can you put the vehicle in gear with no drive, will the pedal lift on its own or do the gears crunch because the clutch isn't dis-engaging???

When the clutch pedal goes and stays on floor with no resistance I can not select any gears, clutch arm on slave doesn't move at all due to the apparent lack of fluid.
Usually the clutch pedal won't return on its own but once bled the pedal works again and disengages the clutch.

Since realising that the clutch usually fails just after starting the engine and the brake accumulator fills with fluid I assumed a vacuum was been created in the fluid reservoir and sucking fluid back from the clutch master.
I made a pin hole in the cap and now (touch wood) everything seems ok.

The cap should definately have a vent hole from what I've read so could be worth checking yours too if you are having trouble with the clutch keeping pressure after bleeding.
 
Last edited:
My clutch master cylinder is fed from a seperated off section of the brake master cylinder, I would think theres enough fluid in the reservoir to supply the brake booster, without pulling fluid from the clutch. I'd be looking at the clutch master cylinder push rod, master cylinder piston for sticking in and check that the C/M cylinder push rod is moving for enough back to allow the port that allows fluid into the cylinder is open.

Have you tried back bleeding the system from the slave cylinder end???


PS.

Quote: "When the clutch pedal goes and stays on floor with no resistance I can not select any gears, clutch arm on slave doesn't move at all due to the apparent lack of fluid."


After re -reading your last post it sounds like you fitted a brand new F@@ked Master Cylinder, that doesn't appear to be forcing any fluid into the system under pressure.
 
Last edited:
This clutch is fed from a separated section of the brake master too, plenty of fluid for the accumulator but before I vented the cap the vacuum created by the accumulator filling would suck from the pipe feeding the clutch master too.

So far, not had any problems since venting the cap :) time will tell...

(Did try back bleeding the system along with about another 8 slightly different ways of doing it, can bleed the air out no problem and get the clutch to work).
 
Hi zzr1200

My p38 does that the clutch is now lighy as hell but i can still select gears and drive and the pedal returns ots self, i did catch my top on the arm at the bell houseing when i was changing my turbo and now i dont know how to readjust my clutch, any tips ?
 
Hi zzr1200

My p38 does that the clutch is now lighy as hell but i can still select gears and drive and the pedal returns ots self, i did catch my top on the arm at the bell houseing when i was changing my turbo and now i dont know how to readjust my clutch, any tips ?

Clutch is self adjusting.
 
Yeah i thought that but since i pushed the clutch leaver on the underside of the bell housing in( pure accident) the clutch has been light has hell and the bitting point is really low

Many thanks
 
Yeah i thought that but since i pushed the clutch leaver on the underside of the bell housing in( pure accident) the clutch has been light has hell and the bitting point is really low

Many thanks

You may have a problem with the roll pins at sometime. Sounds like they are moving.
 
Hello,
I did try to post my own thread on but not sure how to yet so i have replied to this one, i hope its okay.

I was hoping someone on here might understand a problem i am having (again).
I have a range rover p38 mileage 111187 and its a 99 T reg manual 2.5'D, the clutch was slipping just a bit but only
some times till one day it just went all together, anyway i went under it and notice that the clutch slave cylinder push rod had
come out. When i got the gear box of the clutch disc was okay but what i did notice was that the diaphragm spring was bent in on one side and
the pins that go through the fork and fork shaft was snapped so i bought clutch kit pins and clutch slave cylinder put it all back together
just before xmas and its started doing the same thing again, when accelerating it revs up a bit as if the clutch is going, i haven't taken it to bits just yet but i will be. (I did bleed the clutch)
 
Back
Top