1996 RR 4.0 SE hard to stop, pump keeps running

kermit_rr · Oct 9, 2019

When you press the brake pedal, this releases the vacuum from the house which is part of the cruise control system
Pretty sure there should only be vacuum when cruise is activated

brianp38dse · Oct 9, 2019

Make sure you set the brake switch properly when you have finished playing with it.

Rover9676 · Oct 9, 2019

Thanks, so are you saying the brake pedal switch is not working properly or vacuum routing is wrong?

Rover9676 · Oct 9, 2019

brianp38dse said:
Make sure you set the brake switch properly when you have finished playing with it.

I didn't disconnect or bother the brake pedal switch, I just rolled off the vacuum hose to see if there was a change. I then placed the vacuum hose back on the switch. Why would I need to reset the brake switch?

brianp38dse · Oct 9, 2019

Thats ok then, i read it wrong i thought you had messed with the plunger part.

Rover9676 · Oct 9, 2019

brianp38dse said:
Thats ok then, i read it wrong i thought you had messed with the plunger part.

Thanks, I'm entertaining all possibilities. Unsure what to do next?

Datatek · Oct 9, 2019

The pump relay is the usual problem if it's not the pressure switch, are you sure you have changed the correct relay?
From memory the pump relay is a black one and different to all the others.

Rover9676 · Oct 9, 2019

Datatek said:
The pump relay is the usual problem if it's not the pressure switch, are you sure you have changed the correct relay?
From memory the pump relay is a black one and different to all the others.

Thanks for responding! Yes, I changed RL-17 (New Relay) and I had the yellow abs relay (RL-2) CHECKED at a reliable auto motive shop, it checked-good.

Datatek · Oct 9, 2019

Rover9676 said:
Thanks for responding! Yes, I changed RL-17 (New Relay) and I had the yellow abs relay (RL-2) CHECKED at a reliable auto motive shop, it checked-good.

Does the pump stop if you remove the relay?

Rubberknees · Oct 9, 2019

Did you change the pump and pressure switch or just switch, as when I did mine a few weeks back far easier to change as one unit than take pump off replace switch and put back together. Sure someone advised with out care switch could be damaged trying to change it.

Rover9676 · Oct 9, 2019

Datatek said:
Does the pump stop if you remove the relay?

Yes, the pump stops when I remove the Relay. Sorry for the slow response to your question.

Rover9676 · Oct 9, 2019

Rubberknees said:
Did you change the pump and pressure switch or just switch, as when I did mine a few weeks back far easier to change as one unit than take pump off replace switch and put back together. Sure someone advised with out care switch could be damaged trying to change it.

Yes, the pump I purchased came as one unit pump, switch and accumulator already attached. I did swap the accumulator from the purchase pump unit with the accumulator already on the RR to try rule-out a bad accumulator. When that didn't solve the problem I put the accumulator back on the purchased pump unit it came from and installed. Still have same problem. I did notice a pronounced shhhhhh yesterday when I depressed the break pedal. I removed the ducts and traced the shhhhh sound to a brake pedal switch with the vacuum hose that connects to one of the Plenum-Ports. Drove RR yesterday evening, have to push pedal nearly to the floor to stop. Pedal is spongy when first pressed, when released and depressed gets hard. 1996 RR 4.0 SE Automatic.

Rubberknees · Oct 9, 2019

Rover9676 said:
Yes, the pump I purchased came as one unit pump, switch and accumulator already attached. I did swap the accumulator from the purchase pump unit with the accumulator already on the RR to try rule-out a bad accumulator. When that didn't solve the problem I put the accumulator back on the purchased pump unit it came from and installed. Still have same problem. I did notice a pronounced shhhhhh yesterday when I depressed the break pedal. I removed the ducts and traced the shhhhh sound to a brake pedal switch with the vacuum hose that connects to one of the Plenum-Ports. Drove RR yesterday evening, have to push pedal nearly to the floor to stop. Pedal is spongy when first pressed, when released and depressed gets hard. 1996 RR 4.0 SE Automatic.

Did you bleed the air from pump at valve block what it connects to, if not you could have got air into the system

Rover9676 · Oct 9, 2019

Rubberknees said:
Did you bleed the air from pump at valve block what it connects to, if not you could have got air into the system

Thanks for responding, how do you bleed air from the abs pump at the valve block?

Grrrrrr · Oct 9, 2019

Rover9676 said:
I will look for an enabled. Where do I connect it on the modulator?
Thanks

Ezibleed connects instead of reservoir cap. Other end is a bottle of dot 4 that uses about 20psi of tyre pressure from the spare to push fluid through the system. Mine is about 25 years old and still going strong.

Rubberknees · Oct 10, 2019

Rover9676 said:
Thanks for responding, how do you bleed air from the abs pump at the valve block?

I suspect you have air in brake system now and need to do a full bleed. Rave explains how to do it , it is important you follow the procedure step by step to purge all air

wammers · Oct 10, 2019

^^^^^^^^ There is specific method to bleed the system. It MUST be followed to the letter.

Rover9676 · Oct 10, 2019

Rubberknees said:
I suspect you have air in brake system now and need to do a full bleed. Rave explains how to do it , it is important you follow the procedure step by step to purge all air

Thanks, I will have to purchasean Ezibleeder or something similar and do a Full-Bleed. Not sure how long it will take o find an Ezibleeder. I will let you know how it goes. Again I appreciate the help!!

Rover9676 · Oct 10, 2019

wammers said:
^^^^^^^^ There is specific method to bleed the system. It MUST be followed to the letter.

Thanks for the advice. I will follow to the letter and bleed again after work today. I'll use that method again today.
Thank you,

tomcat59alan · Oct 10, 2019

Henry_b said:
I bled my rear brakes when i did the calipers, in a weird way

You do everything in a weird way.

1996 RR 4.0 SE hard to stop, pump keeps running

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