ABS problem on my 90 LSC....help?

[Smokee]

First major problem since I got my LSC. About 2 months ago I noticed the brake pedal getting harder to press and then the nosed dived under hard braking, etc,etc....Amber and red idiot lights on all the time. Checked everything I could see and found wet brake fluid on the drivers side frame rail, right even with the door jamb. I jacked up the car, slid under and useing 2 good shop lights I couldn't see where it was coming from. Then I ran my hand up under the master cylinder and it came back wet.

From the bottom looking up front of car to my right; at this angle I see a round or oval thingy with an allen head bolt, going through it to the firewall. Its all wet and looks recent. So I took it slowly over to a mechanic I trust, and he hooked up the tester to the ABS and it shows a code of 21, main valve not functioning.

My question is: Can I fix this by rebuilding whatever it is thats leaking? I priced the parts, and just about hurled. Autozone wants $1098.00 plus core. I am disabled and on SSI; cant afford that much. Anybody have any advice? Also looking at the Master it looks like there ate three sections all bolted together. Autozone called it a ABS Hydroboost master cylinder; I never heard of one of these things. Theres got to be a cheaper fix than a Grand?

[joeythefixer]

You may be able to get by with just replacing the accumilator (the round thing with the allen fitting) they usually seem to fail before the rest of the system. does the pump work on the master cylinder? does it run all the time?

[Smokee]

The only thing I hear from the engine compartment is the pump for the air bags. I had excellent brakes right up the minute the pedal started getting hard, and those stupid lights came on. You say the oval/round can is called the 'accumulator'? Those I can get here in Phoenix, I think anyway.

Are they hard to change? where can I get the info as how to do the change out?

[joeythefixer]

If the power brake pump does not work then it won't help to change the accumliator. Make sure the pump works first!
the accumliator is very easy to replace, you use an allen wrench in the fitting on the top and turn it counterclockwise. make sure that you pump the brakes with the key off about 50 times to relieve the pressure in the system otherwise brake fluid will spray all over when you remove the accumliator.
Also, there is a relay that powers the brakes, it could be bad too. I would check that first.

[Hizhonor]

The only thing I hear from the engine compartment is the pump for the air bags. I had excellent brakes right up the minute the pedal started getting hard, and those stupid lights came on. You say the oval/round can is called the 'accumulator'? Those I can get here in Phoenix, I think anyway.

Are they hard to change? where can I get the info as how to do the change out?

This is the step by step R & R of the Accumulator.

http://www.thelincolnmarkviiclub.org/documents/tech/brakeAccumulator.pdf

IF you need one, I have one for sale in the classifieds section.

[Drake_tr7]

First off disregard everything you know about master cylinders and brake boosters...it's not like that and dosen't work that way...
This braking system is a different animal than what you're used to. It sounds complicated but, trust me, it's not.
Read, study, and learn how it works and it's not all that difficult to work with.
What ever you do, don't try solving the problem by throwing money at it. ;)

[joeythefixer]

I second that!

[1989LSC]

Get a ford factory shop book, not the chilton crap from the autoparts store. I got mine on ebay. Mitchells on demand would work also if you know a shop that has it. Then you can diagnose the problem from there. Don't change the accumulator until you get the pump running.

[Drake_tr7]

Yeah, chances are it's just a relay or a bad connection. There's a lot of info on here about testing it. Don't expect the pedal feel to help you diagnose it...it don't work that way;)

[Magic Al]

This is the "same" unit as used on the Mark VII

http://www.albeedigital.com/supercoupe/articles/abs-system.html


Of course there is also the Tech Section here:

http://www.lincolnsonline.com/tech/00021.html

http://www.lincolnsonline.com/tech/00188.html


Also, a few pages from the Ford Service Manual

http://thelincolnmarkviiclub.org/Gallery/album89

[DaKat]

http://www.lincolnsonline.com/tech/00021.html
http://www.lincolnsonline.com/tech/00188.html

[Smokee]

joeythefixer: where is this relay at? I have changed $30 worth od relays on the firewall, and I still dont here the pump working!

[Smokee]

Thanks everyone! It looks like I got me some downloading and reading to do before I try spending what money I have on her. I do still have a desent brake pedal for stopping, but not for panic stops! I keep hearing some of you talk about a pump or motor running. Maybe I am hearing it run; I thought all thgis time it was the Air spring pump running. I got my list to start: 1. Jack up car, put on stands, pull wheels, check out wheel sensors. My first project, then I will try to find the ABS sensor relay on the firewall.

I know its there, it least I hope so. Anybody got a wiring color code for the relays wires? That might help.

[joeythefixer]

I'm not sure which relay it is on a 90. I think it's the two relays on the left hand side of the engine compartment above the master cylinder.

[Smokee]

Before I buy any more relays, I thought I would do the brake pedal stomp first to see if the pump motor came on. I pressed the pedal about 50 times and then turned the key to the on position. Nothing happened! So I then checked the fuses. Ok there, so I checked the connections at the relays, sensors and switches. Motor still wouldnt run.

So what could cause the motor not to run? burnt out?

[Smokee]

where can I find a ford factory shop book? of the several places that did have the books, they were strictly ford and had no references to Lincolns of any kind.

I really could use one of those books that had wiring schematics; especially dash wiring.

[Hizhonor]

where can I find a ford factory shop book? of the several places that did have the books, they were strictly ford and had no references to Lincolns of any kind.

I really could use one of those books that had wiring schematics; especially dash wiring.

Ebay ...there's a couple of them on there.

[Magic Al]

http://www.helminc.com/helm/Result.asp?Style=&Mfg=FMC&Make=FCT&Model=MARK&Year=1990&Category=&Keyword=&Module=&selected%5Fmedia=&mscsid=MCDJVNG7AGAF9GU72JE37QFT4MQCBG9C