Brake bleeds

[merc123]

Just put new PBR calipers, pads and rotors on the front (both sides). I bled all the calipers (RR, LR, RF and lastly LF). Then I bled the master cylinder. There is no air that I can find and the pedal gets really hard when pumping. When driving though I still have a spongy feeling pedal.

What did I do wrong or could it just be the pads suck (Wagner TermoQuiets).

 

[nyuk98gt]

merc123:

Bleed, bleed, bleed, then bleed again. Air is sneaky and it takes quite a while to chase it all out. I suggest doing the M/C first, then the four corners, then the M/C again. MotiveProducts.com offers pressure bleeders that work very well (I use one). I am not fussy about vacuum bleeding because air can get past the bleeder screws and make you think that you are pulling a lot of air out of the system when you're not.

Probably not the advice you were hoping to hear but more bleeding is most likely in your near future. (The fact that the pedal stiffens up is a good sign. It means that there is just a little air trapped in there.)

Chris

 

[RallyCobra]

nyuk98gt help me out!

I purchased a motive bleeder, and it didn't do anything! I have the custom cap for ford, and I pressurized the system to 15 on the gauge. I opened the bleed valve, and nothing happened. I ended up bleeding the system old school by pumping the pedal, holding pressure, and opening and closing the bleed valve. Should I have pumped the motive bleeder higher? How do you make it work with the hydroboost in these cars? Do you have to hold constant pressure on the pedal?

merc123 - Pick up some ATE Blue brake fluid. It's a different color from your current brake fluid, so it is easy to tell when you have flushed all the old fluid out. Go in order, left rear, right rear, left front, right front. That is longest to shortest in the flush. Once the color changes, you know you have flushed all the air out, as you have new fluid. Purchase a motive bleeder, that seems to be what everyone else does. Maybe someone can give us instructions since I just haven't been able to get mine to work!

Regards,
RC

 

[crazystang25]

no lf is the closest to the MC. rr,lr,rf,lf is the correct order.

 

[RallyCobra]

crazystang25, are you sure about the brake bleed order? The abs pump looks like it is in the right front corner of the car.

 

[merc123]

I'll keep bleeding then. I know it took almost a whole 20 oz. coke bottle to bleed the M/C out of old fluid from the RR when I flushed the system.

 

[nyuk98gt]

RallyCobra:

You can pressurize the master cylinder to 25 to 30 psig and that should be plenty to get the fluid out of the bleeders. The only thing that I can think of is that there might be a little 'crud' built up in the bleeders and it is restricting the flow. Thus, higher pressure is needed to achieve sufficient flow. I suggest installing new bleeder screws (SpeedBleeders!). But, of course, if you have finished the job then you just need to put "new bleeders" on your to-do list.

You can always call MotiveProducts. They are a good bunch and their customer service is quite good (imho).

Chris

 

[RallyCobra]

I've got to change rear pads out tomorrow, so I'll pump it up to 30 and see what happens. I've got a new bottle of ATE Blue, so I'll use it up.

Ate Super Blue DOT 4 Racing Brake Fluid

Dave W owns that site, and is hooking me up with Corbeau seats. Easy to go back and forth with the ATE gold and blue. Great fluid for track/street, since even when it gets wet, it still has a very high boiling point.

 

[nyuk98gt]

RallyCobra,

Please post an update. Air is great to breathe but it is a huge pain in the rear end when it is in the brake system.

GL with the new pads and the re-bleeding.

Chris

 

[RallyCobra]

Success!

Bright blue fluid comes pouring out the bleeder when the pressure is over 22 psi? on the motive bleeder.

Bled all the brakes, got to the right front, and no fluid was coming out of the bleeder. This is what happened last time. Took the line off the caliper, gobs of fluid. Bad caliper, right?

Switched to an old caliper I had, and no problems with bleeding. Bad caliper right? Not quite. Get this - the car has stainless lines that are not stock. I could see on the 'bad' caliper where the threaded part of the line made an impression on the backside of the caliper piston. This is also the side that I had to put the linings on the belt sander to get more clearance, and beat the caliper on with a sledgehammer. The caliper couldn't open all the way, since it was hitting the backside of the line going into the caliper! I'm not sure what is out of spec. A couple of extra copper spacers will fix it if I use that caliper in the future.

I had the problem with a new set of Mustang Bullitt calipers with the horse on the front. I'm not sure if this is a common problem for people.

 

[nyuk98gt]

RallyCobra:

Excellent! Nice work getting things sorted out.

I am not sure why there is a problem with fitment of the new caliper. It ought to fit since PBR is the standard caliper for the +99's. The Bullitt and Cobra calipers have there own bracket (from what I have read).

If you don't mind, please post another update when you get the new caliper working nicely.

Chris

 

[RallyCobra]

The problem with the Bullitt caliper was the brake line was threading into it so far, it was hitting the back of the piston. This pushed the piston out making it very hard to seat the caliper on the rotor. Also, it prevented the flow of brake fluid, causing the piston not to compress.

When I get some time, I'll take some measurements with a digital caliper and some pics. I have an original cobra caliper to compare to the bullitt caliper.

 

[merc123]

I bled them today again and pedal still gets real hard when pumped. Did furthest to closest caliper, bled M/C three times on each bleeder, and then all calipers again. All fresh fluid came out of the calipers, system is completely fresh. Took it up the road and they were still squishy feeling. They were squishy the whole time until I slowed down to pull into my shop. They felt good then but I think I may have done some sort of double pump. When I let off and pulled up to the shop door and tried to stop they were back to squishy. I'm thinking master cylinder going out?

 

[RallyCobra]

Or a leaking hydroboost? I'm not too familiar with the system, but it relies on the power steering pump, right? Have you checked your PS fluid level?

Operation, Diagnosis and Repair of Hydro-Boost Power Assist Systems

Above link explains some diagnostics for hydroboost. Very interesting stuff.

Time for a powersteering fluid change in my orange car!

 

[RallyCobra]

bled M/C three times on each bleeder, and then all calipers again. ?

What do you mean bled M/C 3x on each bleeder? Do you mean you did each bleeder on the calipers, or did you take something apart on the master cylinder?

 

[merc123]

Master cylinder has 2 bleeders on the side of it.

No issues with power steering or fluid level.

 

[Kilgore Trout]

Bleed it again as many times as necessary.

 

[merc123]

Bled them again today. Noticed that my LF caliper was a dribble when bled like it had the clap and the RF was spewing like a champ. Kept bleeding the LF (about another 8 to 10 times) and took it for several runs and it seems pretty good. We'll see what happens.

 

[RallyCobra]

Merc,
You should have a lot of fluid running out. Something is wrong with the LF. I would take the line off the caliper and see if it runs furiously. If it doesn't, you have a pinched brake line, or something bad upstream. Otherwise, there is something wrong with that caliper.

I had a weak stream at the bleed bolt. It was because my banjo bolt was too long, and bottoming out on the piston, preventing fluid flow. Did you use the copper washers? That could make the bolt too long. Take the caliper off and look inside the banjo bolt hole to see if it is hitting the piston.

 

[merc123]

It's good now Rally. I just kept bleeding that particular caliper and had the steering wheel turned back and forth quickly while I tapped on the caliper.