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1970-1995 Range Rover Classic
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Discussion Starter #1
Hey Gang, here's a brake issue that leaves me scratching my head. While driving on the highway I noticed all 3 (brake,TC,ABS,) brake warning lights came on. At first I thought it was just a glitch until I hit the pedal. There were brakes but the pedal was soft and it travelled way too far. First guess was accumulator ball, but the light didnt pop on when the pedal was pressed. Then I thought it was the abs pump cause I dont hear it running after depressurising the system. But the pump supplies pressure, but only intermittently. When I hooked it up to Rovacom there arent faults. My question is, what can cause the brake pressure to be significantly reduced, yet not cause the abs ecu to register a fault? All info regarding this problem is greatly appreciated.Thanks!
 

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Hey Buddy,
just 4 threads before u posted, (please read all p38 .....brake modulators), read that thread u will learn a lot about it, and I am not assuming that this is ur problem :D good luck!
ZEE
 

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1995-2002 Range Rover P38A
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ABS pump... check connector to pump, its the one that supplies power to the motor, the conector inside tends to slightly open up or time due to the heat cold effect.

If not then it could possibly be the pressure switch on the pump, its the green piece attached with a square multi plug, or it may depending of course be the pump but if it was you would have the 3 amigos up all the time.
 

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1970-1995 Range Rover Classic
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Discussion Starter #4
viperover said:
ABS pump... check connector to pump, its the one that supplies power to the motor, the conector inside tends to slightly open up or time due to the heat cold effect.

If not then it could possibly be the pressure switch on the pump, its the green piece attached with a square multi plug, or it may depending of course be the pump but if it was you would have the 3 amigos up all the time.
Thanks viper, I do have all 3 up all the time. There's moderate pressure in the pedal. On a few occasions when messing with depressuring the system, I've got the light to go out and the pump to run, which caused normal (actually the brakes never felt as good) brake function. Confusing to say the least. I'm wondering if (which is more of a shot in the dark than anything else) the accumulator ball is acting up?
 

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1995-2002 Range Rover P38A
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Just re read your original posting...

If accumalator is worn then normaly the pump will run every time you press the pedal.
Braking effect can also be hampered by the caliper seals being hardened with age and slider pins not cleaned/lubed on each pad change.

You need to determine if the accumalator is original but thats not always a tale tell sign as I've had a few in with relatively new accumalators fitted that have failed prematurely.

A failing ABS pump pressure switch can give you the same symtoms..
If you could borrow a good known accumalator to try it will be ideal, takes a mere minute to remove and refit.

Hows your brake fluid level and condition...
 

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1970-1995 Range Rover Classic
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Discussion Starter #6
Slide pins and the like are fine. I learned the lesson after freeing a seized pin. Fluid levels are ok. Dot 4's in there. Might be a pressure switch, but wouldn't that log somethin in there for rovacom to read? On all the ranges I've owned went the accumulator was goin the lights would flicker each time I pressed the brake pedal. You touched on a good point. The pump would also run after each press of the pedal. So pressure switch is looking more & more viable. Thanks for the insight.
 

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1995-2002 Range Rover P38A
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Yeah, them darn pressure switches are becomming a big issue and Im trying to source a supply of them, they are available loose and the hunt is narrowing down to a supplier.
 

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I've got exactly the same faults with mine, i've got a second hand pump/accumulator/switch assembly coming in the next few days to try and eliminate the switch, I'll keep ya posted on the outcome. I've already replaced the acc with a brand new one.
 

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Sorted! New pump assembly ited with new accumulator and hes back up and running. The old pump worked fine so its gota e the switch on ours ...
 
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