Brake Problems!!!!!!!!!!!! - 5 lug Conversion

bit

Founding Member
Sep 27, 1999
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Anderson, SC
I just put 95 GT brakes on my car, including the master cylinder. I bled the brakes with a vacuum bleeder. When I pumped the brakes they got hard but other than that they go all the way to the floor. They felt like they were not holding pressure. Like a bad master cylinder. Well I replaced the MC. It was bench bled before install. Then the brakes were bled again. This time I pulled 6 bottles of fluid (~6oz per bottle) through each caliper while more was being poured in the MC. The new MC and all this bleeding made no difference in the breaking. The booster rod has also been adjusted many times; right now the brakes are slightly dragging. Does anyone have any ideas?
Thanks
Brent
 
Did you gut the stock PV?
Have the Adj PV fullly Open?

Also I would manually bleed them to. I pulled alot of air out of mine after the vac bleeding by doing it manually
 
This works every time if you don't have a leak or bad parts...

Garden Sprayer Pressure Bake Bleeder

1 each pump type garden sprayer, 1 - 1 ½ gallon capacity (size doesn’t matter much, it just has to be cheap and small enough to be easy to work with)
6-10 feet 3/8” clear plastic tubing
1 each ¼” brass pipe tee
1 each ¼” pipe to 3/8: hose adapter
1 each pressure gauge 0-60 PSI or so – all you’ll ever need is 5- 10 PSI, so the gauge range doesn’t have to be high.
1 each large rubber stopper – this is the hard part to find. It may take some searching to find one that is a snug push fit to the inside of the filler port on the master cylinder. You can use silicone rubber to seal a brass fitting to an old master cylinder cap, but they tend to leak too much.
Home Depot or Lowes has some ¼” brass pipe stock that is continuously threaded in the electric lamp repair department, along with the brass nuts that go with it. This is better than a pipe nipple, since the nuts can be used to secure the pipe in the cap or stopper.
OR if you can’t find the threaded pipe stock,
1 each ¼” nipple, 1 ½”- 2” long

The rubber stopper needs a hole drilled in it for the ¼” pipe nipple or threaded pipe stock. After you drill the hole, use some silicone gasket sealer to seal the pipe nipple as you push it into the rubber stopper. If you used the threaded pipe stock, use the nuts to secure the stock into the stopper.

If you can’t find a suitable rubber stopper, an old master cylinder cap can be used. Drill a ½” hole in the center for the pipe fitting. Cut the brass pipe stock to about 1”- 1 ½” long, the exact length isn’t too important. Push it through the hole in the master cylinder cap and thread one nut on top of the pipe stock where it sticks though the cap. Put another nut on the other side of the cap to lock the pipe stock in place. Apply some silicone rubber gasket sealer to both sides and when it is dry, screw the ¼” pipe that sticks out of the top of the cap into the tee.

Remove the sprayer hose and wand from the garden sprayer. You may find it easier just to cut the sprayer hose off short and connect it to the 3/8” plastic tubing. The idea is that the 3/8” tubing connects to the pickup tube inside the sprayer in a reliable, leak proof fashion. Another alternative is to remove the spray nozzle from the end of the spray wand and connect the 3/8” tubing to the wand. This leaves the hand valve in place and may be useful to start/stop the flow of brake fluid.

The 3/8” plastic tubing connects to the pipe tee using a push on hose barb type adapter. The pipe tee has one port for the gauge, one for the 3/8” hose and the other to connect to the rubber stopper or master cylinder cap that you modified.

Fill the pump sprayer with a quart of brake fluid. Set the garden sprayer on the ground and screw the pump handle down tight, and pump until brake fluid fills the plastic tubing. Then put the modified stopper or master cylinder cap on the master cylinder and pump slowly to make sure that nothing leaks or pops loose. No leaks, continue pumping until you get 5-10 PSI. Put a 6”-12” length of clear plastic tubing on the bleeder ports. Then open the bleeder ports on the wheel cylinders one at a time and bleed until the bubbles are gone. I use a 2 liter soda bottle with a coat hanger to catch the fluid . DO NOT REUSE THE OLD BRAKE FLUID. Repeat the process until you have finished all 4 wheels. You will have to pump the sprayer several times to maintain the 5-10 PSI needed to do the job. When finished bleeding, loosen the pump handle to relieve the pressure, remove the stopper/modified master cylinder cap and test the pedal.

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1991vert said:
brake booster
??

I bled the brakes more(vacuum and otherwise) and found no air. I have not tried jrichker's bleeder yet but I am guessing most of you did not use it on your cars.

I think I have found the real problem. I adjusted on the booster rod out a 1/4 turn and the brakes got better but still sucked. At this position the brakes were dragging slightly. I adjusted the rod out a 1/8 turn more and now the brakes are dragging badly. BUT now the brakes work. What is up with that? I should not have to make the brakes drag for them to work.

I am not sure if the brakes are working as well as they should. From 45 I can slam on the brakes and the car brakes straight and short, but it will not lock up the front brakes. I know this is good for braking, but I would think the car should have enough braking force to lock up the front tires. The tires are very sticky 245/45 Simitomo HTR ZII's.

Thanks for any thoughts
Brent
 
bit said:
I bled the brakes more(vacuum and otherwise) and found no air. I have not tried jrichker's bleeder yet but I am guessing most of you did not use it on your cars.

I think I have found the real problem. I adjusted on the booster rod out a 1/4 turn and the brakes got better but still sucked. At this position the brakes were dragging slightly. I adjusted the rod out a 1/8 turn more and now the brakes are dragging badly. BUT now the brakes work. What is up with that? I should not have to make the brakes drag for them to work.

I am not sure if the brakes are working as well as they should. From 45 I can slam on the brakes and the car brakes straight and short, but it will not lock up the front brakes. I know this is good for braking, but I would think the car should have enough braking force to lock up the front tires. The tires are very sticky 245/45 Simitomo HTR ZII's.

Thanks for any thoughts
Brent

Anyone have any ideas?
 
I had the same problem after doing mine. It turned out to be just lots of old nasty fluid in the system, but since youve flushed yours, i dunno. My car brakes quite well, but wont lock the tires, so dont use that as a guide.
 
Tonys89GT said:
I had the same problem after doing mine. It turned out to be just lots of old nasty fluid in the system, but since youve flushed yours, i dunno. My car brakes quite well, but wont lock the tires, so dont use that as a guide.
Which problem? You had to make the brakes drag before they would work?

Brent
 
Perhaps I missed it but where is the prop valve set at? Sounds as if you have too much pressure going to the rear discs. I will crank the prop valve in all the way (so a majority of the pressure goes to the fronts) and then see if your brakes feel better and the fronts can lock. From there just keep backing off the prop valve until you reach a point where the rear lock just after the fronts.

As for the dragging. Is it only the fronts or is it the rears or fronts and rears? If it is only the rears, make sure the parking brake cable isn't too tight. Also, it will take less for the rears to drag than the fronts since the caliper piston is smaller.

Lastly, did you check the system for leaks? did you gut the factory proportioning valve? Are you using a 94-95 cobra MC with the stock booster?
 
tunedin302 said:
Perhaps I missed it but where is the prop valve set at? Sounds as if you have too much pressure going to the rear discs. I will crank the prop valve in all the way (so a majority of the pressure goes to the fronts) and then see if your brakes feel better and the fronts can lock. From there just keep backing off the prop valve until you reach a point where the rear lock just after the fronts.

As for the dragging. Is it only the fronts or is it the rears or fronts and rears? If it is only the rears, make sure the parking brake cable isn't too tight. Also, it will take less for the rears to drag than the fronts since the caliper piston is smaller.

Lastly, did you check the system for leaks? did you gut the factory proportioning valve? Are you using a 94-95 cobra MC with the stock booster?

Currently the prop valve is set in 6 turns. There are 10.5 turns of travel. I have had the valve at many different adjustments and it really has no affect. I am not sure if the rears are dragging, I have not checked. Even with the transmission in neutral it would be hard to get a good feel for it. I have just been lifting the car and checking the fronts. There is no parking brake on the car.

- No leaks
- Yes I gutted the factory valve
- 95 Mustang GT MC with 91 Mustang Booster.

Thanks
Brent
 
bit said:
Currently the prop valve is set in 6 turns. There are 10.5 turns of travel. I have had the valve at many different adjustments and it really has no affect. I am not sure if the rears are dragging, I have not checked. Even with the transmission in neutral it would be hard to get a good feel for it. I have just been lifting the car and checking the fronts. There is no parking brake on the car.

- No leaks
- Yes I gutted the factory valve
- 95 Mustang GT MC with 91 Mustang Booster.

Thanks
Brent

When you bleed the brakes, the Adj knob should be turned all the way in (full open to the rear). After they are bled then turn the Adj knob back out and then the initial setting is about 4 turns in, I would also look into a SN95 Booster.
 
Shakerhood said:
When you bleed the brakes, the Adj knob should be turned all the way in (full open to the rear). After they are bled then turn the Adj knob back out and then the initial setting is about 4 turns in, I would also look into a SN95 Booster.
The knob is fully open(turned all the way in) while bleeding. I can try changing it from 6 to 4 turns and see what happens.

Thanks
Brent
 
bit said:
The knob is fully open(turned all the way in) while bleeding. I can try changing it from 6 to 4 turns and see what happens.

Thanks
Brent

Full open to the rear is the correct way to bleed as it is hard to get air out of the rear lines so you want full force going back there. You can also tap on the rear calipers with a mallet to help release trapped air.
 
After driving the car for 2 days and 160 miles, the brakes are no longer dragging. The petal has gotten soft at the top. I am going to adjust the rod out again and see what happens.

Brent