Brake fluid leak with PICTURE !

Can anyone tell me why this would pour fluid from the backside into the frame? What exactly is this called? This is on a 1988 Thunderbird Turbo Coupe. The pic was taken from below looking up and foward. Thank you very much!

http://www.zjstech.net/~library/5558/leakvalvesmall.jpg




[This message has been edited by sofakingfast (edited 12-29-2004).]

If I turn the ignition on and sit, there will be a sizaable puddle in just a few minutes. The fluid is not coming from above this valve it is from the valve and dumping into the framerail. Also the sensor screwed into it is leaking from the pins in its connector. What is this this senor for? I assume brake pressure. But is it used by the ABS?
The fliud seems to be coming from a sort of weep hole in the left side of this valve if that helps. And only really starts to puddle with the ignition on. Overnight the puddle is very small. Only a dime size. With the ignition on it will be 3 inches in diameter in a minute!

That is the pressure sensor that the PRC uses to switch the shocks to FIRM mode when system pressure exceeds 400 psi. The solution is to replace the switch. After switch is replaced, you will need to bleed the front brakes. That is the good news. The bad news is that I would bet that the switch is obsolete from Ford, and probably not available from Ford. Could always just put a pipe plug in there if you cant find a replacement switch. Maybe someone here with a parts car will sell you a used switch for a few $$.

As far as the valve goes, could the brake line fitting just need to be tightened up?

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Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 21 psi, forced air intercooler, water injection, bypass valve, Ranger roller cam, subframes, etc., etc.. // 86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP nitrous, ignition, gears, suspension, etc., etc.... // 91 Escort: Bone stock winter car // 04 Taurus Duratec (wifes car)

[This message has been edited by Jeff K (edited 12-29-2004).]

I had the exact same issue. It is leaking from between the plastic and the metal sleeve. The part is still available in places, but it is upwards of $300 to get ahold of it. I just put a plug in there from a Cougar, I think it was. There are several cars with the same brake tree that have a plug in that whole.

Forgot to mention: I replaced the PRC with Sensatracs a long time ago, so replacing that part with a plug was a non-issue for me.

I had to replace that on my '89 SC about a year ago. I believe, at that time at least, Ford still made the part. If they can't find it have them look it up under an '89 SC. It was about $99 for that little switch, but nowhere near $300!

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~Matt~
'89 Thunderbird SC 5-speed
'87 Thunderbird TC 5-speed (2nd place '83-'87 TC class at 2004 All-Ford Nationals)
[email protected]

Probably the same part with a different part number!

#*!& I hate that

Thanks for all of the helpful information. This pressure switch is obsolete from Ford. I will try to scavange the yards and the net to find a used one.
I'd rather have it working. The car is completely original. With only 80,000 on it.

Does anyone know what the threads are on the pressure switch? Are they NPT? Reason I ask, is I just looked at pressure switches at McMaster Carr, and they have adjustable pressure switches rated at 10,000 psi max operating pressure in NEMA 4 weatherproof enclosures. Fitting is 1/2" NPT male. THere is also a NEMA 1 indoor rated one with 1/4: NPT male connection. Indoor one could be "ruggedized" for use under the hood, I would think, like coat it with a layer of RTV. Set point can be adjusted from 100 to 1500 psi. They are about $67. Could probably be adapted to fit whatever thread is in the prop valve. They have SS pistons saled with buta-N, which I THINK is compatable with brake fliud. Of course, the electrical connector would not work, but that is an easy problem to overcome. If anyone wants to check it out, go to www.mcmaster.com/ and search for #3427K86, or look under pressure switches, on the first of the 3 pages that come up.

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Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 21 psi, forced air intercooler, water injection, bypass valve, Ranger roller cam, subframes, etc., etc.. // 86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP nitrous, ignition, gears, suspension, etc., etc.... // 91 Escort: Bone stock winter car // 04 Taurus Duratec (wifes car)

[This message has been edited by Jeff K (edited 12-29-2004).]