Loosing brake fluid
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Elder User
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From: Kitchener,Ontario,Canada
Loosing brake fluid
slowly....... but also have long pedal travel. Thought it was coming out the M/cylinder reservoir cap, but now I see wet brake line at the aluminum distribution block (is that the proportion valve)below the master cylinder. Had a RABS light on about 6 weeks ago & found reservoir was down.Topped it up & the light went out.
On the aluminum block there is a flat headed bolt with a hole in it, on one end of the block (near to master cylinder). That is where the leak seems to propogate from.
Whats the best thing to do now!?!?!?
Pedal holds firmish, but is almost down on the floor. However brakes still work good at the moment (booster works well). Constant pedal pressure is possible without the pedal sinking to the floor, so I think the seals in the m/cyl seem to be good. Whats bothering me is the leak, if I can stop that & bleed the sytem I think I'll be good again. Last fall I had off the brakes & no leaks at the wheel cylinders. I need to know more about that aluminum block!
Regards, Aeroman.
On the aluminum block there is a flat headed bolt with a hole in it, on one end of the block (near to master cylinder). That is where the leak seems to propogate from.
Whats the best thing to do now!?!?!?
Pedal holds firmish, but is almost down on the floor. However brakes still work good at the moment (booster works well). Constant pedal pressure is possible without the pedal sinking to the floor, so I think the seals in the m/cyl seem to be good. Whats bothering me is the leak, if I can stop that & bleed the sytem I think I'll be good again. Last fall I had off the brakes & no leaks at the wheel cylinders. I need to know more about that aluminum block!
Regards, Aeroman.
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From: Kitchener,Ontario,Canada
Originally Posted by Pablo-UA
There are 2 small rings on small oiston beyoung the spring inside the alluminium box. They leak.
Any more info greatly appreciated !
Aeroman.
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From: Wichita
Whether it's leaking internally or not, it doesn't seem like the external fittings should leak because of it. Is this bolt you describe a banjo fitting? If it is, did you try to tighten it? Maybe the brass washers are bad.
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Originally Posted by Aeroman59
On the aluminum block there is a flat headed bolt with a hole in it, on one end of the block (near to master cylinder). That is where the leak seems to propogate from.
Your low pedal is due to this leakage and/or mal-adjusted rear brakes.
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Only once or twice have I felt the RABS come on during slick roads or panic stop. The panic stop elicited a large, strong, intermittent pedal sensation quite unlike the rapid, small pulsations on newer vehicles. It was a rather scary sensation as the brakes were being applied, then suddenly no brakes, then brakes again. I'm not all together certain the RABS was operating as it was supposed to. After that experience, I'm rather reluctant to have it happen again.
The slick road (snow covered) was done deliberately (on vacant roadway) to test the RABS system. I could feel the brakes being applied, then released and reapplied, but nothing like the strong reaction during the panic stop affair. Of course, the snowy road application was at a considerably lower speed of approx. 20-25 mph.
The slick road (snow covered) was done deliberately (on vacant roadway) to test the RABS system. I could feel the brakes being applied, then released and reapplied, but nothing like the strong reaction during the panic stop affair. Of course, the snowy road application was at a considerably lower speed of approx. 20-25 mph.
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Gentlemen,
I had exactly the same scary experience with my rabs system. I removed the system and installed a manually adjustable proportioning valve and my brakes were no longer scary but among the very best I have experienced. Rabs sucks.
Ken
I had exactly the same scary experience with my rabs system. I removed the system and installed a manually adjustable proportioning valve and my brakes were no longer scary but among the very best I have experienced. Rabs sucks.
Ken
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From: Kitchener,Ontario,Canada
Brake fluid Leak confirmed.
Originally Posted by aerocolorado
That is the accumulation chamber for the RABS valve. When the RABS is activated, fluid is displaced via a small piston which travels back into the accumulation chamber, during the pulsations. The hole in the bolt is to allow air to excape as the piston moves backward into the chamber. Of course, it also allows road grit to build up over the years. The piston seals catch the grit and upon return, the seals start to leak. Sounds like its time to replace the valve assembly.
Your low pedal is due to this leakage and/or mal-adjusted rear brakes.
Your low pedal is due to this leakage and/or mal-adjusted rear brakes.
Time to change the valve (RABS ?) unit. I'm hoping I can get a new one. Although if not I guess this w/e I'll be at the junk yard.......
Well, it was time to change the brake fluid anyhow !!
Thanks again,
ATB Aeroman
Last edited by Aeroman59; Jan 16, 2008 at 12:39 PM.
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From: Portland, Oregon
I felt it... and kinda heard it???????????? idk, i was going down a hill, and had to make a sudden stop, and i mashed the brake pedal down and felt a small pulsing and heard a series of clicks that slowed with the car (sounded like it was coming from under the dash.)
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Originally Posted by Aeroman59
Time to change the valve (RABS ?) unit. I'm hoping I can get a new one.
Even if your valve block was not leaking, it could still require replacement from another internal problem source. The two solenoids/valves sit undisturbed for years at at time. Brake fluid is hygroscopic (water loving) and will pull moisture from the air over time. The water eventually corrodes the valves in the RABS assembly. When the time comes for them to spring into action, they either stick shut or fail to return, once open.
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From: Kitchener,Ontario,Canada
Originally Posted by aerocolorado
Rebuilt ones are available at most parts stores. New ones are outrageously expensive.
Even if your valve block was not leaking, it could still require replacement from another internal problem source. The two solenoids/valves sit undisturbed for years at at time. Brake fluid is hygroscopic (water loving) and will pull moisture from the air over time. The water eventually corrodes the valves in the RABS assembly. When the time comes for them to spring into action, they either stick shut or fail to return, once open.
Even if your valve block was not leaking, it could still require replacement from another internal problem source. The two solenoids/valves sit undisturbed for years at at time. Brake fluid is hygroscopic (water loving) and will pull moisture from the air over time. The water eventually corrodes the valves in the RABS assembly. When the time comes for them to spring into action, they either stick shut or fail to return, once open.
Saturday might be a long day!
Aeroman.
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From: Tottenham Ontario Canada
Originally Posted by ken1mod
Gentlemen,
I had exactly the same scary experience with my rabs system. I removed the system and installed a manually adjustable proportioning valve and my brakes were no longer scary but among the very best I have experienced. Rabs sucks.
Ken
I had exactly the same scary experience with my rabs system. I removed the system and installed a manually adjustable proportioning valve and my brakes were no longer scary but among the very best I have experienced. Rabs sucks.
Ken
Ken: Aside from removing the solenoid, is there anything else that needs to be done to remove the system? Since my van is now a work truck and I frequently tow a small trailer, I need reliable braking.
Cheers,
Eric
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From: Kiev, Ukraine
Are they rubber O rings of round cross section? can I get to them from that flat head bolt. Haynes manual says air in the rabs system cannot be easily bled & needs special equipment!
__________________________________________________ _________________
This is small tool depressing prop. valve spring fully. Else you will spend more time to bleed system.
__________________________________________________ _________________
This is small tool depressing prop. valve spring fully. Else you will spend more time to bleed system.
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From: Kitchener,Ontario,Canada
Update
So I have not fixed the RABS valve yet. My son got stuck in his Mustang & had to get towed back . Flat battery caused by no charge from alternator due to I/P warning bulb not connected! (he had his dash panel disconnected!). Had to think back a few years to remember that problem & you wont find it in too many manuals.
All's good now with the Mustang, also wired up his new Stereo & took out all the redundant wiring from the last owners installation., but I still need to make a trip to the wreckers yard & temp is dropping to -11*c by w/e , so I'm not too much looking forward to the job.
Still I'd be even less into paying $250 + for a shop to do the job.
Better than cabin fever though.
All's good now with the Mustang, also wired up his new Stereo & took out all the redundant wiring from the last owners installation., but I still need to make a trip to the wreckers yard & temp is dropping to -11*c by w/e , so I'm not too much looking forward to the job.
Still I'd be even less into paying $250 + for a shop to do the job.
Better than cabin fever though.