compete brake loss

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compete brake loss

Postby rkmark7 » Thu Oct 06, 2016 2:53 pm

Anyone experience complete brake loss? I mean "I now need a clean pair of shorts" blow through an intersection loss? 1990 LSC
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Re: compete brake loss

Postby CDW6212R » Thu Oct 06, 2016 3:04 pm

Hi, welcome, and are you and the car okay?

Don't drive it again until you check out the brakes. Do you notice if both dash lights are on for the brakes, one yellow and one red? These cars have a brake pump and an accumulator, which stores the brake pressure. If there isn't enough stored pressure, the brakes will be very poor or almost non existent.

The weakest link of these TEVES brakes is the brake accumulator. That must function, and over time it doesn't store as much pressure, it wears out. The best test of that is to have the car running, and mildly apply the brake pedal. The ABS pump is loud enough to hear clearly if you listen. Does it run every single time you press the pedal, or once say every three times etc? If the pump runs every time or always, the accumulator is likely bad.

Don't let the ABS pump run too much, that is not a constant duty pump. It's only meant to run occasionally, and it will last nearly forever if it's not run too much.

The accumulators are unavailable in the stock part number right now. There is mention of a couple of options in other threads here, search around and find those. It's likely one of the other model accumulators(Jaguar is the one I recall), will fit and work fine. They just unscrew and screw in, when the pressure is bled off first(pump the pedal a bunch of times with the key off).
Don
1991 Red Special Edition, my 2nd SE, dead paint, DWS 255/45/17's on 95 Cobra wheels, and soon; DVD/Navi/backup camera, OBDII and the 347, before custom paint.
98 Mountaineer with Continental DWS 255/55/18's, big sway bars, custom brakes. Soon to be A4WD with XP8 bumpers and wing.

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Re: compete brake loss

Postby rkmark7 » Thu Oct 06, 2016 9:24 pm

Thanks so much. i currently have an 84 mark 7 BB that i have been tinkering with and almost have it ready. I have been thinking about getting rid of it. It only has 84,000 on it but as the dash is electronic,feels under powered and the seat will not go back far enough to be comfortable. My neighbors wife has a Black 90 LSC which is in fabulous shape. My coveting of this car led to my purchasing the 84. the neighbors husband stops the other day and says his wife blew through the intersection and thanks to guardian angels no one was hurt. Had to clean her underwear but will now not drive the car-period. he wanted to know if I wanted the car. Feels he can't sell it so if i wanted it he would have it towed to my house "And you can have it". My wife is about ready to shoot me but--oh well. One has to do what one has to do. i just got off the phone with the shop that worked on it. this is what they found:
could not replicate the problem-customer said she "stood on the pedal to stop (one foot) the pedal was hard but the car would not stop." They had a difficult time getting it to give up a code but finally came up with code 88. Pressure sensor switch? They felt this might have been the problem but were not sure. That if I replaced it I needed to replace the ABS pump motor relay also. That this is an electronic system-that there is no power booster. But in order to replace the switch you needed to have a "special tool" (socket?) Brake fluid sensor tool?
i will take it around the block tonight and down the street after all the kids go to bed and see what happens. Love the looks of the car but there is now sense in having it if one cannpt get it to stop or i should say you can't trust it.

again, thanks so much for your quick response. Tonight I will try what you suggested and let you know.
Randy
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Re: compete brake loss

Postby CDW6212R » Thu Oct 06, 2016 9:52 pm

Good luck with it Randy, you can fix it readily if you learn about the basic components, which are discussed many times here, in various related threads about the brakes. You can diagnose it without driving it, and you don't need a code reader for the brakes, or special tools really.

The accumulator is the weakest link, that one part is easily 50 times more likely to fail than the rest of the brake parts.. It is not a bad part, it simply stores fluid pressure, inside a small thick steel ball, with a bladder inside, and high pressure nitrogen I believe. Over 10-20 years, it will not hold as much pressure.

Then the problem begins to damage the rest of the parts, as they are not made to run continuously. That's why you must not drive it, that can end up costing way way more. The ABS pump is super rare and expensive, buying another used one is the best choice then.

Confirm the functioning of the ABS pump, that tells you that the pump should be good, and also the pressure switch, and the relay. Clean brake fluid is critical, dirty fluid in these systems can ruin the pump, don't let the fluid get too old. Simply replace the brake fluid every couple of years. Put that on your must do now list.
Don
1991 Red Special Edition, my 2nd SE, dead paint, DWS 255/45/17's on 95 Cobra wheels, and soon; DVD/Navi/backup camera, OBDII and the 347, before custom paint.
98 Mountaineer with Continental DWS 255/55/18's, big sway bars, custom brakes. Soon to be A4WD with XP8 bumpers and wing.

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Re: compete brake loss

Postby Falkon » Fri Oct 07, 2016 8:18 pm

Her you are. Complete description of the system on the cars.

Also search Lincolns on Line site for all the tests etc. (tech).


http://www.sccoia.org/articles/anti-loc ... ng-system/
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Re: compete brake loss

Postby rkmark7 » Sat Oct 08, 2016 3:33 pm

Good info, thank you. Sometimes finding the information on how to fix something is more difficult for me than the actual repair.

The best test of that is to have the car running, and mildly apply the brake pedal. The ABS pump is loud enough to hear clearly if you listen. Does it run every single time you press the pedal, or once say every three times etc?
After starting it, I believe I hear the pump about every 2nd time it press on the brake pedal.

Going through the paperwork on the car last night I realized that they are the original owners. Couple of items popped out-over the years it appears to like to hav eth ebattery replaced fairly often and the AC seems to leak pretty regularly. interesting what invoices tell you.

Randy K
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Re: compete brake loss

Postby MarkVII88 » Tue Oct 18, 2016 3:17 am

My post at the link below will hopefully be all you ever need to work on your Mark VII's brakes!

http://www.thelincolnmarkviiclub.org/phpBB3/viewtopic.php?f=5&t=9714#p80919

If the accumulator is being charged after only 2 pumps of the brakes it sounds like it needs replacing. When mine needed replacing it was being charged every time and after I replaced it I got 3 pumps before it was charged again. Even if the accumulator was bad though there still should have been enough pressure for stopping at an intersection? Even when both my brake lights were on the car still stopped when a goof in a stopped Jeep pulled in front of me and I had to stand on them.
'88 LSC (totaled)
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