Range Rover p38 2.5 auto

Could a duff accumulator cause the pump to continously run and not build pressure I wonder.

There are some on eBay but for the price I may as well buy the abs unit

Flossie said:

Could a duff accumulator cause the pump to continously run and not build pressure I wonder.

Click to expand...

With a duff accumulator the pump usually does stop but starts again immediately you touch the brakes.

Datatek said:

With a duff accumulator the pump usually does stop but starts again immediately you touch the brakes.

Click to expand...

My old one was doing that, first press and it's away. New one is 2nd press.

If the pump runs until pressure is reached then can you not force the pressure sensor switch wiring to say "at pressure"/"not at pressure" to check the pump switches on/off as commanded?
If that test works but the pump continuously runs in normal operation then that says either the sensing switch is duff, or the pump has insufficient output to get to pressure, or you have a leak in the tank/lines.?
I thought the finger test for pump pressure was a simple one?

Flossie said:

My old one was doing that, first press and it's away. New one is 2nd press.

Click to expand...

Air in the system?, did you pre-charge the new accumulator with fluid?

DanClarke said:

If the pump runs until pressure is reached then can you not force the pressure sensor switch wiring to say "at pressure"/"not at pressure" to check the pump switches on/off as commanded?
If that test works but the pump continuously runs in normal operation then that says either the sensing switch is duff, or the pump has insufficient output to get to pressure?
I thought the finger test for pump pressure was a simple one?

Click to expand...

Eas pump is the finger test Shirley?

DanClarke said:

Air in the system?, did you pre-charge the new accumulator with fluid?

Click to expand...

No air, positive about that.
Didn't think pre charging was a thing tbf.

Flossie said:

No air, positive about that.
Didn't think pre charging was a thing tbf.

Click to expand...

I thought they said to squirt brake fluid into the accumulator to fill it until refusal and then quickly spin it over and screw it on.

DanClarke said:

If the pump runs until pressure is reached then can you not force the pressure sensor switch wiring to say "at pressure"/"not at pressure" to check the pump switches on/off as commanded?
If that test works but the pump continuously runs in normal operation then that says either the sensing switch is duff, or the pump has insufficient output to get to pressure?
I thought the finger test for pump pressure was a simple one?

Click to expand...

The finger test is for the EAS, I would not recommend you try it on the hydraulic pump.
The pressure switch is not a simple single contact on/off switch.

DanClarke said:

I thought they said to squirt brake fluid into the accumulator to fill it until refusal and then quickly spin it over and screw it on.

Click to expand...

No need to do anything with the accumulator release all pressure all pressure from the system, 30 pedal presses according to RAVE, unscrew the old one and screw on the new one.

Datatek said:

The finger test is for the EAS, I would not recommend you try it on the hydraulic pump.
The pressure switch is not a simple single contact on/off switch.

No need to do anything with the accumulator release all pressure all pressure from the system, 30 pedal presses according to RAVE, unscrew the old one and screw on the new one.

Click to expand...

Ooops sorry, quite right.

I have made two videos of to share but I can’t up load them on here, I will try and convert them,

Please let me know your thoughts??

Flossie said:

Not sure.
But the pump is working yes?
But the pump isn't turning off now, yes?
To me, anyway , sounds like the pump is getting a constant 12v so more like the relay is fused closed or fusebox wiring issue. I'm not convinced you have tested the relay terminals in the fusebox properly either as has been explained by others more knowledgeable than me.
Not a criticism at all but if you don't understand what they meant by the testing then ask again.
I'm not sure I would trust a meter made by rolson either , most of their stuff is crap.

Click to expand...

Agreed, if it stopped when you pulled the relay. Go straight for the relay!!
Don't forget it commands the pump to run only.

Have you seen the two videos I posted that I made this morning? I have two new relays and the pump won’t work with either installed but pump works when bridged

I can only give you the same thoughts as I already have.
In your second vid the 1st and 3rd test don't show anything you don't know already, and its not the issue.

The 2nd and 4th test are the 1s that need looking at.

Switch the meter to show volts, switch on the ignition and find which of the 2 shows volts (10 "O" clock on your meter) You found it earlier in 1 of your posts. This will be a switched live with ignition on. If you dont have volts there is a fuse that supplies that.

Now its the other 1, that is the 1 you need to check with it on your present setting it needs to go to earth ( I.E you get 0 on your meter) if the requirement of the pressure switch is met.
So push the brake pedal half a dozen time to ensure there is a low pressure in the system first.

Until this wire is checked as to why it is not going to earth then its guesswork.

J

Ok

So as it too hot outside I went to the garage with me meter.
Please not the relay sockets and the meter setting.



Pic 1 shows permanent live.




Pic 2 & 3 show the socket's of concern this is ignition on and brake pedal has been pushed many times. Checking voltage.



Pic 4 ignition off.



Pic 5
Ignition off (meter change) checking for ground, good enough



Pic 6
Put the relay back in and turned on the ignition, the pump ran for 20-30 seconds, turned off ignition and removed relay, No ground as pressure switch has switched.


Pic 7
Same situation as above but I put it on the same meter setting as you have been using.


Hope that helps

J

Faizey76 said:

Click to expand...

Hi mate, I am sorry but I am thoroughly confused. The second film clip says checking relay volts but the meter is set to 200 Ohms resistance not Volts.
So any resistance over the selected range maximum will give a default reading of "1".
If you set the Multimeter to the 20Volt DC range and go across the relay control circuit pair you will see if it receives a "GO/Operate" voltage.
You have already proved the other side of the wiring is fine with your jumper because your pump fires and runs and then stops after a while (presumably until it reaches a required charge pressure for the system).
So you need check that there is 12V or greater on one of the relay coil pins and a switched earth on the other.
I believe that most of the control Ccts are turned on by switching the earth path, so Ccts fail IF the control switching itself fails OR the continuity to an earth on the other side of the switch point has failed.
I am a novice at this but have managed to fix my problems (so far).
Someone like Keith @Datatek is far more knowledgeable than I.