| Author |
Message |
    
Jose A Cabrera (Jcabrera)
| | Posted on Thursday, January 16, 2003 - 12:19 am: | 
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96 Disco
I have been having major issues with my brakes.
Pedal down to the floor as I drive. Once pumped they work fine.
Replaced brake M/C
Bled entire systems 5 or 6 times by now
No leaks
Problem still there.
Dealer claims: perhaps ABS valve (over the phone, they have not inspected the rig) have appointment for Monday.
What happens if I remove the ABS fuse? Would this cause any damage? Is it safe to drive? Has anyone removed the entire ABS system? |
Jose A Cabrera (Jcabrera)
| | Posted on Thursday, January 16, 2003 - 05:29 pm: |
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any help/comments? |
blake
| | Posted on Thursday, January 16, 2003 - 05:39 pm: |
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I removed the fuse because the pump kept cycling when I had a loose sensor. Brakes work fine, just no ABS. |
Tim Ballard (Tballard)
| | Posted on Thursday, January 16, 2003 - 07:43 pm: |
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I now always disconnect the ABS system (by pulling the connector at the pump) for trail use. The brakes work fine, and you are actually able to lock them up and slide to a stop on sand/gravel, which is impossible with the ABS system on. |
OLIVER CLOTHSOFF (Everythingleaks)
| | Posted on Thursday, January 16, 2003 - 07:43 pm: |
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If the dump valve is sticking removing the fuse will not help. The dealer is right though, the problem may be in the valve block. LR sent out a bulletin back in mid-90's about hot flushing ABS systems on RRC. The process was to microwave the fluid to a warm temp and then flush the system. It actually did bring pedal feel back in the RR brake system but never tried it in a disco ( brake systems are different). Shouldn't hurt it though. |
Jose A Cabrera (Jcabrera)
| | Posted on Thursday, January 16, 2003 - 09:39 pm: |
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Tim,
Can you please tell me which connect and what/where is the pump?
blake: you refer to the fuse on the fuse box in the engine bay...right?
Thank you guys! |
Ron
| | Posted on Thursday, January 16, 2003 - 10:20 pm: |
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RR and discos are completely different animals. I have never seen an ABS modulator go bad in such a way as to cause the issue Jose is having.
If you pull the connector off the ABS modulator it will take it out of the system and the system becomes just a standard power brake set up. On a RRC it makes it a MANUAL brake system. RRC brakes are a nightmare though very nice while working.
My first guess would still be it is not bled properly. How are you bleeding it?
The other possibilities are the proportioning valve (in theory this could be it) or vacuum related though vacuum issues are normally manifested in a hard pedal.
One other check which should be done is to clamp off the rubber hoses and see if pedal feel improves (obviously not while moving  ) If it still sucks it rules out caliper leaks.
Ron |
muskyman
| | Posted on Thursday, January 16, 2003 - 10:41 pm: |
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Quote:If you pull the connector off the ABS modulator it will take it out of the system and the system becomes just a standard power brake set up
not really true, unplugging the pump simple deactivates the pump the fluid still goes thru the pump and if the pump has a mechanical problem such as being frozen from moisture or seized it will not act like a standard power braking system.
I have seen bad pumps cause a soft pedal, this is most often combined with a muffled sound when the pump is activated such as if its running under a pillow.
still I would first bleed the system again as I do agree with ron that it is most likely just air in the system. |
OLIVER CLOTHSOFF (Everythingleaks)
| | Posted on Thursday, January 16, 2003 - 10:56 pm: |
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You are right Ron, I have never seen a valve block fail on a disco like that either. It was just a possibility looking at the other roads he has been down. I came in kinda late on this problem but if I remember correctly this problem happened before he changed the master cylinder but I don't remember if the vehicle had any fluid loss and thats why it was changed. The valve block was about the only thing after your hose idea I could think of besides what has already been done. What about the pressure reducing valve? I've never had a problem with one but what if it was failing. Would it send fluid from one side of the master over to the other and cause pedal fade? I wouldn't think so but it was made in England.
P.S. - key word in RRC statement is when they work. If you think the disco brake parts are expensive look at brake parts for the RRC and 4.0/4.6. They fail a lot more also |
Jose A Cabrera (Jcabrera)
| | Posted on Friday, January 17, 2003 - 12:31 am: |
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Thank you so much for all the information:
Ron: I bled the system the old way. One person pumping the pedal, I under the rig with the plastic hose attached to the nipple and the other end into the plastic bottle. We did it 3 or 4 time. Then, I took it to a garage. I have not found a place where they perform pressure bleeding thingy. What do you suggest to properly bleed systems?
Muskyman: no muffled sound that I can tell.
Oliver: I had no leaks prior to changing the master cylinder. I based my decision on the original symptoms (same as now) and the fact that I have 103K miles.
Keep all the ides coming, tomorrow a friend and I will be working and inspecting the brakes one more time. Hopefully we can find the problem and save the many hundreds of dollar the dealer will change on Monday. |
perroneford
| | Posted on Friday, January 17, 2003 - 07:58 am: |
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Jose,
You cannot effectively bleed an ABS equipped truck with the old technique of pumping the pedal and bleeding the nipples. This is why you probably have a soft pedal.
By a bleeder from Motive Systems. It's cheap and works great. British Pacific also offers them if you want to support a LR vendor.
-P |
muskyman
| | Posted on Friday, January 17, 2003 - 10:45 am: |
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I should have stated that I have not seen a ABS pump/modulator fail in a disco/rover...but I have seen a number of them fail in BMW's and GM products. but they all do work the same way.
sorry had no intention of misleading anyone |
Mike Urquhart (Ironmike)
| | Posted on Saturday, February 08, 2003 - 09:05 pm: |
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Hello anyone,
I am new to LR Discovery. Is it possible to check the ABS sensors myself? If so where can I find the sensor on a 94 Disco?
Mike |
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