ABS pump runs continuous

rover86 · Oct 8, 2014

Hi guys, just returned from town & the abs pump will not stop running. I have unplugged the power plug to it, the pump was quite hot. RRC 1994, any advice would be most welcome. Genral mechanice are no problem for me but I have not come across one of these pump type systems before. I really must get out more.!!

Saint.V8 · Oct 8, 2014

Stuck relay...common fault or bust pressure switch....again common

pete1987RRC · Oct 8, 2014

Or a failed pressure vessel

Check relay first

Datatek · Oct 8, 2014

pete1987RRC said:
Or a failed pressure vessel

Check relay first

Pump should still stop with a failed pressure vessel, it will just run with every brake press.
As Saint said, relay most likely, or pressure switch.

rover86 · Oct 8, 2014

Datatek said:
Pump should still stop with a failed pressure vessel, it will just run with every brake press.
As Saint said, relay most likely, or pressure switch.

Thanks to all the replies, I'm thinking it is possibly the pressure vessel, I waited till the pump eventually stopped, applied brake & 2nd press on the pedal it started the pump, ran for about a minute before it stopped. Will try the pressure switch first as that looks the easiest & cheapest.

Saint.V8 · Oct 9, 2014

rover86 said:
Thanks to all the replies, I'm thinking it is possibly the pressure vessel, I waited till the pump eventually stopped, applied brake & 2nd press on the pedal it started the pump, ran for about a minute before it stopped. Will try the pressure switch first as that looks the easiest & cheapest.

From your description above it is most likely the accumulator.....

Datatek · Oct 9, 2014

rover86 said:
Thanks to all the replies, I'm thinking it is possibly the pressure vessel, I waited till the pump eventually stopped, applied brake & 2nd press on the pedal it started the pump, ran for about a minute before it stopped. Will try the pressure switch first as that looks the easiest & cheapest.

If the pressure switch is the same as the P38, it's an arm and a leg if you can even find one. Again, as Saint said, pressure vessel ( accumulator) is most likely.

classic kev · Oct 9, 2014

Try accumulator first. Did mine two weeks ago ('91 RRC), accumulator (genuine) was £100.00 delivered from Island 4x4, an easy job BUT, you have to bleed the system and this can be a nightmare, make sure you have at least 5 litres of brake fluid available. If you're lucky it will all bleed easily but the ABS system can take a lot of fluid to bleed. make sure you follow the workshop manual bleeding procedure to the letter.

Once done the pump should run for no more than 45 secs to pressurise and if all is good, the pump shouldn't come on again for 4 or 5 presses of the brake pedal and then only run for a short time to repressurise. HTH

wammers · Oct 9, 2014

Even if the accumulator is knackered and has lost all it's Nitrogen charge, the pump should still stop at some point when the system is up to pressure. Even though it will start again pretty quickly if brake is applied. Accumulator may or may not be knackered but it's certainly not that causing pump to run continuously. Sounds like the pump is not making pressure for some reason to me. If the switch was duff you would expect the pump to burn out running against pressure at some stage.

Saint.V8 · Oct 9, 2014

wammers said:
Even if the accumulator is knackered and has lost all it's Nitrogen charge, the pump should still stop at some point when the system is up to pressure. Even though it will start again pretty quickly if brake is applied. Accumulator may or may not be knackered but it's certainly not that causing pump to run continuously. Sounds like the pump is not making pressure for some reason to me. If the switch was duff you would expect the pump to burn out running against pressure at some stage.

Tony, read his second post with further details!

wammers · Oct 9, 2014

Saint.V8 said:
Tony, read his second post with further details!

Ok accumulator fubarred then. Note to self. Must read more.

rover86 · Nov 29, 2014

Thanks for all the replies, accumulator changed, along with pads front & rear & changed some of the rusty pistons too, bleeding......bit of a pain but all spot on now. I'll just move onto the next thing which needs sorting now...no abs on the front axle as someone has changed it !!!

ABS pump runs continuous

rover86

Member

Saint.V8

Dyed-in-the-wool 100% RR Junkie

pete1987RRC

Well-Known Member

Datatek

Well-Known Member

rover86

Member

Saint.V8

Dyed-in-the-wool 100% RR Junkie

Datatek

Well-Known Member

classic kev

Well-Known Member

wammers

No longer with us, RIP

Saint.V8

Dyed-in-the-wool 100% RR Junkie

wammers

No longer with us, RIP

rover86

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