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Discussion Starter · #1 ·
On the ABS accumulator... has anyone tried BOSCH 0265202070

On the ABS Brake Pressure Switch... these things are tough to find. Does anyone have a reasonable source? (up until a year ago they were easily found on Amazon for ~$65)
 

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Discussion Starter · #3 ·
Regarding the pressure switch... is it a fact that even if the pedal is pumped 30+ times to remove pressure from the accumulator, I will still need to bleed the system after replacing the pressure switch?
 

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1995 and 1996 P38 Range Rover 4.6 HSE
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I've just been through the whole brake issue thing and thought it was the pressure switch for awhile. After a lot of research I came to the conclusion that it is better buy a replacement pump rather than the pressure switch. I'm guessing a lot of people came to the same conclusion so they stopped producing just the switches?
 

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Hmm, not one I've ever seen. How it can identify the switch has failed I'm not sure. If it runs the pump and the pressure switch doesn't close within a certain time (and flags the fault), it could be that the switch has failed but equally it could be that the pump is working not not reaching the required pressure to operate the switch. Does the pump run and then shut off as it should? The switch is actually 3 switches in one so it may be that one isn't working and it is detecting that? This will be much like the EAS faults where the description doesn't always match the actual fault but just give a pointer to the symptoms.
 

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Discussion Starter · #7 ·
Somewhat difficult to reliably ascertain if the pump runs continuously since the vehicle is at college with my son. It does seem to be building pressure as he reports the feel if the pedal is unchanged (it is normal).

My plan is to replace the accumulator first since I have no idea how old the current unit is. After that, clear faults and re-assess. I will have a switch on hand if need be.
 

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Discussion Starter · #9 · (Edited)
update: the pump is NOT running continuously and pedal pressure remains normal.


I appreciate that, but no gauge and less than perfect set of circumstance. Diagnosing from afar will definitely cost me some extra in parts. Gotta play the hand that is dealt.

I purchased a complete unit from a truck that was being parted out. So I will have a switch, block, accumulator, and pump on hand (though all are 'suspect' by the very nature of being recycled).

Two years ago parts were relatively easy to find. That appears to be dwindling. Time to stock up on wear items and other bits that are known to fail.
 

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Make sure you have the switch wiring diagram to hand so you can check with multimeter. Also ABS unit & brakes will probably need a bleed after swapping the pump, especially if the replacement is empty.
 

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1995-2002 Range Rover P38A
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Another test for the accumulator: Press brake pedal 20/30 times without ignition, then turn ignition on and measure the time until the TC warning light extinguishes. Should take less than 45 seconds. If more, then it´s a good thing to swap the accumulator sphere … easy job.
 

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Other way round, 30-45 seconds is good as it is filling the accumulator, less than that and there is little or no Nitrogen left in it. More than 45 seconds means the pump is getting weak.
 
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Discussion Starter · #13 ·
I'll install an new accumulator simply because I have no idea how old this on is and hey, it is the brake system and my kid is driving so, better safe than sorry. I generally don't like throwing parts at a problem but again, I am dealing with less than ideal circumstances.

Will I need to bleed the system after I swap the accumulator? If yes, will I need to bleed the entire system, or just a specific section?
 

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normally after replacing accumulator, system simply requires a top off. rule of thumb whenever opening a hydraulic system it is wise to bleed pressure before and air after performing task.
 

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Other way round, 30-45 seconds is good as it is filling the accumulator, less than that and there is little or no Nitrogen left in it. More than 45 seconds means the pump is getting weak.
Ooops, makes sense! THX for correction ...
 

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Discussion Starter · #16 ·
normally after replacing accumulator, system simply requires a top off. rule of thumb whenever opening a hydraulic system it is wise to bleed pressure before and air after performing task.
I'm confused. Sounds like it will just need a top off. Your rule of thumb clashes with that view however.
 

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yes, many of us have gotten away lucky with replacing with out bleeding, but it is advisable to bleed. you can try your luck.
 
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