Yes, another brake? I have looooked though thtreads!

sc91gt

Registered User
My abs light has been on since I owned my bird and now I am getting the hard pedal red brake light when I drive. It's a 90' sc. It is parked. I have 93 spindles, 04 mustang calipers, new rotors, stainless lines to install and have been researching converting to non abs. From the hours of research on here I am still confused on what mastercylinder/booster comb I need. Conflicting numbers set up and what have you. I went to the junk yard today and there was a 93 marquis right next to a 90 ls cougar. So I pulled the master cylinder off the marquis. then the one from the 90 cougar to compare, because the booster off the 90 cougar is what I thought i was supposed to use. And there is no way the MC will work with that booster. Can you use the MC from the cougar and just plug the two lines on the left side? I am very mechanically inclined, could someone give a direct breakdown of what I need and do? One of the conversion post I read through said it was a straight swap of parts but then 4 pages in it said you had to be careful and measure the pushrod length. According to that post with the parts mentioned the mastercylinders would work. But today at the junkyard, not so much. Please help. Got to get the bird back on the road. Thanks, Shawn
 
I can tell you what I did, and it works great.

I only had to change one nut (ferrule) to make it all work, too!

I took the non-prop-valve version of the base 1991 Thunderbird/Cougar master cylinder, the non-ABS booster, and one M10-1.0 brake bleeder.

The booster goes in against the firewall, the MC bolts right up, and the two front brake lines bolted right up to one pair of ports (the pair closer to the firewall for me), I then took a spare cable from the proportioning valve on the frame rail (pulled from the junkyard) and replaced the nut at the top with a M12-1.0 unit (got THAT from the boneyard I got my core MC from - cut all four lines off there so I'd have spare nuts!) That went to the front port on the outside, and the bleeder to the front port on the inside (inside == towards motor, outside == well, the other way.)

I'm having to put in a connector for the low-fluid sensor, but I can add a few pics here, and somewhere here I have the Cardone part numbers I used. I'll post this and edit it with pics later - I have to take them first :D Ignore the partially disassembled motor, I'm getting it back together this week (and yes, it's a 5.0HO ... )

Here's one of the master cylinder from across the driver's fender:

Cougar_Master_Cylinder.jpg


Outside (driver's side) showing the two ferrules. The one to the front of the car goes down to the proportioning valve to the rear brakes, the one to the rear of the car goes to the passenger front (hey, that's how the ferrules fit!)

Outside_Ferrules-Front_Rear_Brakes_Rear_Passenger_Front.jpg


Here's of the inside (passenger) side. Bleeder in the front port, driver's front brake in the rear port. Note: If you swap front and back on both sides, it should still work great. It's how it all fits for you, more than anything.

Inside_Ferrules-Front_Bleeder_Rear_Driver_Front.jpg


And I used the vacuum tee to the outside (driver's side) of the MC to get my vacuum from.

Vacuum_Tee.jpg


RwP
 
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sure.

I have searched thoroughly,and have not been able to find a straight shot. needed parts, and placement. At this point, I am going to bite the bullet ande send my abs into scp to get rebuilt. For $650. :( seems outrageous for a car this old. brakes should be simple. I am all ears to a solid solution. I have read some post that u have been on, but still confused as to what I need to get it done.
 
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Does the pump motor run at all.....

Before you ditch the system, try and find out what the problem is first....

I've done simple things like cleaning the terminals on the ABS pump motor relay to fix a hard brake pedal condition.....
 
I picked mine up from Ohio and drove to VA with the hard pedal & the problem was nothing more than the relay for the ABS. It had been abused by water, replaced that for about $65 and all has been good w/ the brakes...

A car this old may roll across Mecum's auction block some day for some substantial $$ :) If you can keep the "high tech" brakes of the day.... well, just sayin :)
 
The first time it acted up was the night I left on a roadtrip and though I was going to have to turn it around. Constant red light and hard pedal. I checked fluid, fine. Relay seemed to be clicking on. I pulled the electrical connection from the round sensor deal (pic)
photobucket-5957-1333295192591.jpg
[/IMG] on the front of the MC Cleaned it and put it back on and the brakes worked like they always had.?The red brake light has always flashed hitting brakes. Occaisionally a little hard pedal on panic stops but would smooth out. The kid I bought the car from had a junkyard one in glove box and I think he claimed that was the issue. But if you saw how much stuff he had screwed with on this car I do not have alot of faith. So I am going to replace that and see what happens.
 
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Have you ever replaced the accumulator ball with a new one.....

Flickering brake and ABS lights are an early indication of the accumulator going bad....

Try this:
Turn ignition switch on.....
Listen for pump motor to cycle on, then off....
How many seconds did it take to pressurize the system....
Apply the brakes....
Does the pump motor cycle an and off....
If the pump motor comes on as soon as you apply the brakes, then the accumulator is weak....
 
The accumulator is the black ball thingy behind the reservoir and under the windshield cowling.....

It might even have a hex fitting for an allen wrench on top of it....
 
Just a note - I did add the pictures I promised. Better late than never.

Mods - feel free to bust that message out and post it to the conversion thread.

RwP
 
It sounds like the accumulator went bad, but it was never fixed ... so the pump motor ran more than it should have ... so now, either the relay went bad, the motor brushes are worn out, or maybe the pressure switch is bad. The good news is, you should be able to narrow down exactly what the problem is, and it's probably fixable for a few hundred at most. The 35thATR website has great troubleshooting info. And Big E can help guide you as well.
 
The big E has helped me narrow it down to the pressure switch. So I am trying to find one to replace it with. Anyone know where it can be sourced?
 
They felt good at first, but then got a bit spongy.

Since I was using the junkyard booster with my MC, I figured it was just going bad. Sure it was - the MC had sprung a leak! (I think by my wife pumping too hard when I was bleeding it, but eh.) I picked up a new one from RockAuto for both, and even without the full bleed I'm doing this weekend, they feel much firmer ...

I'll let you know after I get the full bleed (and the new PBR calipers in the front!)

RwP
 
Ralph.. what the heck is that on top of your engine?

That's the old ABS harness.

It doesn't STAY there, I keep it down between the new MC and the fender - but pulled it out to make the pics better.

One of these days I'll bust open the wiring harness and remove all of that.

But not for now - too much work to do, not enough time.

RwP
 
Ralph.. what the heck is that on top of your engine?

LOL...

Looks like someone accidentally put a 5.0 in there. :p ;)

If it's any help on the swap, I took some pictures of my swap before engine was re-installed...one pic is in my garage: HERE

Finding the right combo is confusing. The MC can be found in early 90's CV's...I think mine came out of a 92 (non-ABS of course) The booster came out of base-model Tbird (non-ABS again)...I want to say it was a 91.

The reason using the T-Bird MC isn't used is because the fluid pressure is applies in a criss-cross pattern, one line controls the driver front and passenger rear calipers, the other line controls the the passenger fornt and driver rear calipers. The SC is different - the fluid pressure is applied to the front calipers separately from the rear. It's been awhile since I thought it through, but technically you COULD use the T-bird setup, but you would have to replace lengths of brake lines as well, since the SC tubing doesn't match the base-model.
 
I was referring to the black case-like thing. There is no supercharger apparent in the picture either. Did you swap in a 5.0?

Ahem.

1991 Cougar XR7. It's got the 5.0HO as its motor. They dropped the 3.8SC for the Cougars that year - only the Tbird SC gets it from 91 to 95.

No, I didn't swap in, that's what it has.

Same ARC, same ABS, same springs, etc. etc. as a SC ...

You may notice I don't talk much about the motors themselves here :D But especially as I figure out the suspension and electricals, I'm more than glad to toss in what I know.

RwP
 
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