PBR caliper swap complete..Problems...

phils89sc

Registered User
First, it was a little more than just a caliper swap, since I had an 89, I had to swap into 93-97 spindles. So, after inspecting a little closer, I found that I needed lower control arms as well, (uppers are new), so I purchased a new set of Moog control arms, left and right front lowers. This project took me all day, but I wanted to make sure I did everything right. I loaded the suspension during reinstallation of the control arms, struts, etc. I used new bushings for the strut rods where they go through the control arms.

Anyway, I loaded up my 99 GT PBR calipers with new brake pads and hardware kit. I installed new Raybestos front brake hoses as well, might as well cover everything right?

On the drivers side, I had to modify the PBR caliper near the boss near the forward facing caliper slide. I had to grind off some of the material on the caliper there where it comes close to the spindle. Other than that, the new brake line with the course thread Thunderbird banjo bolt bolted right up.

On the passenger side, I had to go a little further with the caliper. I had to grind down the same boss near where the caliper meets, plus raised area near where the brake line bolt to the caliper. This allowed for me to bolt up the Tbird brake line, but the weird thing was I had to use the Mustang banjo bolt on this side because the thunderbird one was course thread where the caliper was fine thread (different from the other side), so the only thing I can think of is that these calipers (which I bought used), but be from different Mustangs (year / model).

Anyway, after grinding on the caliper, I got everything bolted up, had my wife work the break pedal so I could bleed the front brakes. Everything worked well, and I went for the test drive. The car rides like new! No more rattles and noises coming from the front, and the braking was very nice, smooth and powerful....until I pulled into my driveway. I pulled into my drive way and the brake and ABS lights come on and stay on. I still have brakes, but they feel kind of stiff.

I also could not hear the ABS pump motor running, but it had to have been because the pedal was not super stiff.

Do I need to bleed the rears as well? Could my pump motor be shot?

Oh, and another thing. I could not hook up my ABS sensors from my 89 to the 93 spindles. They simply would not fit in the hole! I found this odd because I have done this spindle sway before on another SC I had and the 89 sensors fit in the holes on the 93 spindles, they were just a little short. What gives?
 
I am not sure, but I think there is a thermal switch on the motor....

On my 89, the pump ran all the time until it just wore out....
 
I did the same upgrade and found out that 90 ABS sensors didn't fit the 93+ spindles. Even with a new set of 93+ ABS lines the connectors do not match and will not plug into the car.

I've been wondering if I can somehow splice that ABS cables?
 
I did the same upgrade and found out that 90 ABS sensors didn't fit the 93+ spindles. Even with a new set of 93+ ABS lines the connectors do not match and will not plug into the car.

I've been wondering if I can somehow splice that ABS cables?

I don't know if this would work, but I was thinking about either taking my dremel to the hole for the sensor and opening it up, or a very large drill bit.
 
The early model sensors are not long enough to reach the ABS rings. I think you can take off your hubs and have the rings press in a little so the early model sensors reach.
 
If the brake light came on with the ABS, I believe your fluid level is too low.

The sensors are the same, hall effect, just different connectors. I would cut the connector off your old knuckles and splice it into the new sensor so you don't have to cut the harness on your car, just at the knuckle. Solder the wires together, and seal it with a liquid electrical tape or glue encased heat shrink. These connections need to be perfect, as the voltages involved in these sensors is fairly low.

My 90 wiring and my 93 wiring show the wire colors at the wheel sensors should be the same. There should be 3. One ground, and 2 signal wires. Each pair of signal wires has one with a black stripe, and one with some other color stripe.
 
If the brake light came on with the ABS, I believe your fluid level is too low.

The sensors are the same, hall effect, just different connectors. I would cut the connector off your old knuckles and splice it into the new sensor so you don't have to cut the harness on your car, just at the knuckle. Solder the wires together, and seal it with a liquid electrical tape or glue encased heat shrink. These connections need to be perfect, as the voltages involved in these sensors is fairly low.

My 90 wiring and my 93 wiring show the wire colors at the wheel sensors should be the same. There should be 3. One ground, and 2 signal wires. Each pair of signal wires has one with a black stripe, and one with some other color stripe.


The sluid level was fine, braking was even, no pull at all from one side to the other. Felt good. I am getting ready to go to the parking lot in a minute to listen for the relay and pump motor.
 
Ok, so I went out during lunch and turned the key on to see if the ABS pump motor and relay were working. I turned the key on and went to the ABS MC under the hood. You could hear it turning, albeit not nearly as loud as it should be. Usually, it is pretty audible and you can feel it in the pedal. Not now though. I was looking at the accumulator ball and it while the ABS motor was running, the ball was vibrating a bit (hold the laughter, please :). You could hear the motor or something in that vicinity gurgling as if it had air bubbles in the lines.

I had the system open to the air to replace the calipers and it did not do this with the original calipers and brakes. Do I need to bleed the rear brakes as well? The relay seems to be working, the motor is working, but slower than it should. I keep thinking that maybe I did the bleeding on the fronts wrong or something.

What is the correct process for bleeding these brakes, front and back?

Thanks,
Phil
 
What is the correct process for bleeding these brakes, front and back?

Thanks,
Phil

On the Teves Mk II?

Turn car on, let system pump fluid levels up.

Verify plenty of fluid in the reservoir.

Bleed passenger rear, then driver rear.

Turn car off, pump the accumulator out.

Bleed passenger front, then driver front.

Cross fingers and pray nothing springs a leak :mad:

OR - just yank the ABS off, upgrade to conventional brakes, and bleed in the same order.

RwP
 
Just to clarify Ralph's post.....

To bleed the rears:
Turn ignition switch on and let pump charge accumulator (lights should go out)
Have a helper press on the brake pedal and then crack open the bleeder (do RR first then LR)....
Turn ignition off and then add brake fluid to reservoir....:rolleyes:
RF and LF are done in the standard conventional way with the helper pumping the brake pedal, then holds pressure on the brake pedal while the bleeder is opened....
Repeat pedal pumping until all air is out of brake lines....

We just did this to my 89 5 speed this weekend.....:D
 
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Update on abs brake issue... If I let the car sit for about an hour, I can come out, turn on the key and hear the pump motor running, but it does not sound right and it runs for a good two minutes before it stops. Once it stops, the pedal gets about two pushes before the lights come back on and the pedal goes hard, however, the motor will not come back on till you let it sit for about thirty minutes. So, when it did this a few minutes ago, I removed the pump motor relay and jumpered pins 3 and 4 to get the motor to run manually. I used a paperclip to do this and after a few seconds of running, and still it was gurgling and running slow, the paperclip was too hot to touch!

Does this sound like the motor is failing and just Bethune, shutting off, and tripping the thermal circuit in the motor? Could it still be a problem with just the accumulator? Thanks for everyone's help!
 
If the brake light came on with the ABS, I believe your fluid level is too low.

The sensors are the same, hall effect, just different connectors. I would cut the connector off your old knuckles and splice it into the new sensor so you don't have to cut the harness on your car, just at the knuckle. Solder the wires together, and seal it with a liquid electrical tape or glue encased heat shrink. These connections need to be perfect, as the voltages involved in these sensors is fairly low.

My 90 wiring and my 93 wiring show the wire colors at the wheel sensors should be the same. There should be 3. One ground, and 2 signal wires. Each pair of signal wires has one with a black stripe, and one with some other color stripe.

Now that the pedal is rock hard with no assist, I have noticed something else. The motor will run when the key is turned to the on position for about 1.25- 1.5 minutes then it will stop and no matter how much I pump the brake pedal, it will NOT come back on. Also, if I wait about and hour, I can got back out and repeat this, turn the key on, let the motor run and it will click off and again, nothing from the motor. The motor sound like it is running very slow and gurgling. It speeds up a little a few seconds before shutting off.

Another weird thing is the fluid level in the reservoir. When I first put it back together on Sunday, I made sure the fluid level was correct. After the pump runs as mentioned above, it is normal, but before that, and after it stops, it is at the top or slightly higher than the arrow that is pointing down on the level indicator ( you know, the two arrows, one pointing up, the other down, and the fluid level should be right between them)
 
Now that the pedal is rock hard with no assist, I have noticed something else. The motor will run when the key is turned to the on position for about 1.25- 1.5 minutes then it will stop and no matter how much I pump the brake pedal, it will NOT come back on.

You should check and see if power is going to the motor when it stops. Power feeds from the relay, through the pressure switch, to the motor. Try to measure power on the wire coming out of the pressure switch.

If you have power through the pressure switch, but the motor isn't running, then it sounds like there is a problem in the motor windings that are causing it to heat up, and stop running. If you don't have power at the pressure switch when things shut off, it could be a problem with the wiring.

You just have to try and trace things down. Make sure you are seeing battery voltage at these test points.
 
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