F

fluffykeith

New Member
Hi
My 1999 P38 2.5D has a brake problem.

Started as the 3 lights on the dash staying on which according to the book means lack of pressure.
Fluid is not leaking out.

I changed the accumulator as the most likely suspect.

After changing the accumulator, bleed the brakes. Couldn't start the car due to battery but could run the pump which turned off after about a minute.

Waited 3 days to get a new battery and put that on, started up and all 3 lights went out as they should and the brakes worked great as I drove up and down the road for a few minutes.
This morning went to use it and the brakes are soft, and the three lights stay on.

Any idea?
 
Pressure Pump...
Pressure Pump switch...
Incorrect Bleed Procedure (must be done as per RAVE instructions to the letter)...
 
Saint.V8 said:
Pressure Pump...
Pressure Pump switch...
Incorrect Bleed Procedure (must be done as per RAVE instructions to the letter)...
Click to expand...

Yes as above,bleed not just calipers by foot and pump, but also there are two bleed nipples in the master Reservoir must be done in the correct order.

You would know if you had a leak as the pump would empty the pipe when you have the ignition on like when bleeding a caliper with the pump on
 
I'm guessing that as it worked first time after bleeding it then I did it right. I followed the Rave method.



Is it possible that the pressure switch is stuck in the off position?

So it could also be the pump relay then?

I need to see if it runs when the brakes fail.



Is it possible to be something in the modulator - I know nothing about how it works but I assume it has solenoid valves, one for each wheel. But for the loss of brakes a part common to all wheels must be failing.



thanks
 
fluffykeith said:
I'm guessing that as it worked first time after bleeding it then I did it right. I followed the Rave method.



Is it possible that the pressure switch is stuck in the off position?

So it could also be the pump relay then?

I need to see if it runs when the brakes fail.



Is it possible to be something in the modulator - I know nothing about how it works but I assume it has solenoid valves, one for each wheel. But for the loss of brakes a part common to all wheels must be failing.



thanks
Click to expand...
Give the pedal a few pumps , open bonnet switch ingnition on you should hear the abs pump fire up for a while then stop , if its making a ticking noise this could indicate lack of fluid other than that diagnostics I'm afraid .

Good luck

Ps no harm in re bleeding just in case a soft peddle usually indicates air.
 
Last edited:
defender300td1 said:
give the pedal a few pumps , open bonnet switch ingnition on you should hear the abs pump fire up for a while then stop , if its making a ticking noise this could indicate lack of fluid other than that diagnostics i'm afraid .

Good luck

ps no harm in re bleeding just in case a soft peddle usually indicates air.
Click to expand...
+1
 
Just an update.
Started it this morning and surprise - no brakes ! Moved it to the drive and listened for the pump - deadly silent.
So I pulled out the relay and checked the connections, no earth on the coil side. Funny I thought. So browsing RAVE I found that the pressure switch is open circuit. Short the conections 1 and 2 on its plug and the pump fires up.
I should have tested that before changing the accumulator!
Will let you know if it fixes it when I change the switch.
 
fluffykeith said:
Just an update.
Started it this morning and surprise - no brakes ! Moved it to the drive and listened for the pump - deadly silent.
So I pulled out the relay and checked the connections, no earth on the coil side. Funny I thought. So browsing RAVE I found that the pressure switch is open circuit. Short the conections 1 and 2 on its plug and the pump fires up.
I should have tested that before changing the accumulator!
Will let you know if it fixes it when I change the switch.
Click to expand...

You can't buy them new let me know if you can but as far as I am know you got to buy secondhand
 
Sorry - got diverted by tv, etc

I only searched around a bit (saab part 8994071) seems to return us prices of $300 and stocsk seem sparse.

There are going to be a lot of scrap P38s (if there arn't already) because of a single component.!!
 
fluffykeith said:
Sorry - got diverted by tv, etc

I only searched around a bit (saab part 8994071) seems to return us prices of $300 and stocsk seem sparse.

There are going to be a lot of scrap P38s (if there arn't already) because of a single component.!!
Click to expand...

That's why people buy them second hand including the pump and then they have a spare pump ;);)
 
Just to update you on progress. I fitted an ebayed pressure switch and re-bled the brakes. All seems to be ok.

Probably the next problem lying in wait is the EAS. It took forever to pump up. I had the battery out for the 3 weeks it was sitting about so I guess it had zero air in it. Bit bumpy going down the lane at first !!
 
fluffykeith said:
Just to update you on progress. I fitted an ebayed pressure switch and re-bled the brakes. All seems to be ok.

Probably the next problem lying in wait is the EAS. It took forever to pump up. I had the battery out for the 3 weeks it was sitting about so I guess it had zero air in it. Bit bumpy going down the lane at first !!
Click to expand...

Leaking pressure side, weakening compressor i would guess.
 
wammers said:
Leaking pressure side, weakening compressor i would guess.
Click to expand...

The back pumps up first followed by the front which is very slow.
If I raise it to the maximum then disconnect the battery (or leave the door open) will it deflate noticably after, say, 5 days.
 
fluffykeith said:
The back pumps up first followed by the front which is very slow.
If I raise it to the maximum then disconnect the battery (or leave the door open) will it deflate noticably after, say, 5 days.
Click to expand...
The back should always raise first to prevent dazzling other drivers if the lights are on. If it stays up for more than 24 hours it's not too bad, I think LR say 10mm drop in 24 hours is permissible. If the airbags are original, they will probably be leaking a little, they have a design life of 7/8 years 80K miles.
 
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