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1992 Range Rover 3.9 EFi - Brakes/Brake Pedal Behaviour


Dickie_L_J_O

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Good evening,



Since owning my 1992 2 Door Manual, I have always experienced odd brake pedal behaviour.


When I go to touch the pedal, it kicks back at me 80% of the time. I get some minute travel at first, then I feel the hard push back. Usually this is accompanied by harsh initial braking, which can be very jolting in slow traffic. Reapplying the pedal after letting off usually allows me to modulate the braking force better. After the kick back, the pedal is very hard.


This also happens with the ignition off.



Another symptom of something not being quite right is the ABS pump. When I first got the car I could always hear this pump whirring when I switched the ignition on. At first I thought it was the fuel pump, but have since learnt it is the ABS pump. This comes on for about 45s when the ignition is first switched on.


If I switch the ignition off for a few seconds and turn it back on again, I can hear the pump going again, but this time for about 3-5 seconds. Something to note is that, with the ignition on, if I press the brake pedal, the pump kicks in again for another few seconds.


The ABS pump itself looks newish, it must have been replaced in the past couple of years looking at the condition compared to the rest of the system.




I have lived with the car for a few months and had just assumed this was a RRC 'thing', I have no experience to suggest otherwise.


The reason for the forum post now is a near miss on a drive to the mountains this weekend gone. The car two in front slammed on the anchors for a pedestrian crossing. I reacted, but the stopping power wasn't as great as I expected and with further pedal force the wheels locked. I narrowly escaped an accident. Thankfully no coffee was spilled. Either way, the lack of ABS worried me somewhat, so now I'm coming to you lot for advice.



Any said advice gratefully received.



- Richard

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The behaviour you describe when you turn the ignition on of the ABS pump running for about 45 secs is fairly normal. However I suspect that the system is not bled correctly and you have some air in the system still. The pump shouldn't run every time you press the brake pedal.

When you turn the ignition on do you get the three ABS check lights, that go out leaving just the red one to go out once you get over 5mph?

You will feel the pedal moving as the ABS operates. Almost a vibration through the pedal.

Something doesn't sound quite right though. Needs more info first. Could be numerous things, faulty ABS sensor, reluctor ring problem, wiring problem, modulator block problem or ABS ecu problem. Hopefully something simple.

Welcome to te forum by the way. Can you edit your profile to let us know where you are. You never know, another member could be round the corner to help.

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As above, the pump operation is pretty normal, also as above, probably had a little air in the pump and/or reservoir(bomb), you should get 2-3 pumps before it kicks in. It's either air, or the bomb is dead, and needs replacing. Procedure for bleeding is in RAVVE, which you should get if at all possible.

You can read the codes out of the ABS ECU, so for your pedal feel issue, I would start there. After a quick google, you can find it here, with all the codes: http://www.rangerovers.net/forum/8-range-rover-classic/25706-rr-91-abs-problem.html#post231820

A properly set up RRC ABS system will be extremely good, with only light pedal pressure needed, so once fixed it'll probably put you through the windscreen :)

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Thanks for the replies.

The only lights I get on coil are the handbrake/brake light, Trans 'box temp, Batt, Oil and one ABS light. These all go out once started (Expect the Brake and Trans 'box light until the handbrake is released).

The ABS doesn't operate, so I'm not getting kick back because of locking and ABS operation. As I say, the same swell and push back can be felt with the car off, key out and battery disconnected...

I've tried reading the codes with the blue connector, but was getting no action from the ABS lamp when bridging the black and pink/black terminals.

I'm based in Zürich, so not many RRC owners around the corner to help. I can update anyway.

- Richard

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Hi Richard,

I have been on holiday for the last week, so I didn't see your reply.

Have you managed to get anywhere using the link that Bowie69 posted above?

I bought this a few years ago to help me with mine when I had a problem http://www.jewellamberoil.com/sales/index.php?main_page=product_info&products_id=230

I did find it useful.

Then there is this page too that might be helpful, http://www.falconworks.net/abs/new_pump_classic.htm

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  • 1 month later...

UPDATE

_________________________________________

Good evening,

The other week I had a suspicion my ABS light was hooked up to my oil light as they would always go on and come off together. Then I was 100% positive of this when I saw then flicker off together one morning.

This would explain why I could never read any codes from the WABCO ECU.

Anyway, this weekend I replaced the accumulator and flushed the system with new fluid. On a side note I found my accumulator had one of the threaded fastener legs cut off and the other thread just resting through a hole in the inner wing. I'm not sure how this is meant to fitted on LHD models, as I could see no holes that would line up for it. I drilled some of my own in the wing and mounted bracket down rather than bracket left. I had to re-do the hard line anyway as I'd cut to remove (seized), so relocating wasn't a drama.

Anywho, back to the real issue.

I pulled out my dash binnacle and had a look at the wiring, sure enough a black wire had been bridged to a white/brown wire. I didn't bother looking up pin-outs and reconnected the cut black wire that was jammed quite far up the loom.

I rested the binnacle back and performed the ABS fault code read. I got code 2-3. Google just gives me other similar forum threads asking what 2-3 is. It's unlisted in my 'how-to' guide.

Reading through these threads it comes up (occasianally, as they're rarely answered) with faulty pressure switch. My pump/pressure switch assembly seem to be shiney and new. The pump also runs and cuts out, kicking back in on the 3rd hard pedal press (with the new accumulator). So surely the switch is working?

Any other ideas, or better diagnosis of code 2-3?

- Richard

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