Losing brakes

[dirtydog427]

I got brake pedal loss of pressure problem as I run it for 20 30 minutes..It seems to be boiling the fluid (it has been hot here in North texas) when I go out to have some fun.. At first the pedal is real firm and then it gets softer but the loss comes all at once usually after I have been bringing it down hard from over 100 of so.. It still seems to have a little brake and I am out in the farm roads so it hasn't been a disaster..it's like just the rears are working and my bias pedal doesn't have much rear dialed in..Then after I slow down in 5 minutes or so the pedal will come back to normal... could a caliper be sticking and how do I find out which one.. I have heard a squeal when I back up some times?? any help would be greatly appreciated.. this is a 92 build with the delux frount end but I don't know if it's Mustang II or MG frount end .. it doesn''t stop worth a s___ when the pads are cold.. and not too much better with em hot...thanks for any help

[GREENHOUSE]

You might try changing your brake fluid, it sounds like the fluid is old or you boiled the fluid at one point (alot of hard braking or track use). Also take the off brake pads and replace them with new ones or lightly block sand the old ones to knock .the glaze off of them.
Mike

[dirtydog427]

thanks Mike --I did rplace the fluid ,, I guess I could go to some stuff with the higher boiling point.. I have jumped up and down on these brakes since I got it back running in order to get them to bite.. I think I put cleaner on the pads when we put the frount wheels back on.. I have put about 1200 miles on it in the last 1 1/2 months and the soft pedal deal just came up in the last 2 weeks.. Does Unique have a pad with more bite? I don't care if it chews up these rotors..U can see on the rotors that these pads arn't biting..Thanks again...

[GREENHOUSE]

Check to see if you have any brake lines near a heat sourse even an exaust leak. Call the boys at unique for new pads, if your pads are jest sliding on the rotors that would make a whole lot of heat enought to cook the fluid. Your pads may look good but not work worth are darn. Make sure the wheels spin free when the brakes are cold.
Mike

[mkassab]

thanks Mike --I did rplace the fluid ,, I guess I could go to some stuff with the higher boiling point.. I have jumped up and down on these brakes since I got it back running in order to get them to bite.. I think I put cleaner on the pads when we put the frount wheels back on.. I have put about 1200 miles on it in the last 1 1/2 months and the soft pedal deal just came up in the last 2 weeks.. Does Unique have a pad with more bite? I don't care if it chews up these rotors..U can see on the rotors that these pads arn't biting..Thanks again...

When did you chg fluid and do the other "stuff" you mentioned above... i.e., did this problem begin right after you chg'd the fluid? If so.... that's more than likely the issue. Did you use high quality DOT 3 or 4 fluid? Did you bleed in proper sequence... back right, back left, front right and lastly front left?

Or, was the problem before you changed fluid and that's why you changed it? If so, most likely not the fluid at all... you'll need to check calipers and pads.

Mark

[dirtydog427]

Thanks Mike and Guru.. What Mike says makes the most sense right now.. It never had brakes that seemed satisfactory.. It was built in Evergreen Co at 8000 ft and could have been winter or was winter in the fact that the frount end and chassis got all salted up..so the pads might never have bedded properly..It always seemed like they were greased or not grabbing.. I changed the fluid about 2 months ago when we got the engine back in and I started driving it.. and I used good fluid .. I have an 04 ZO6 that I am always changing the fluid in so I used good fluid .. But I think this app calls for racing fluid because the little clynders sit right on top of the left header..which are coated.. but still get hot enough to melt the paint.. that's another problem... Thanks for the help guys --new pads and better fluid should keep me out of the cornfields !!! Now how do u eliminate the bump steer?? Hah-- Later on that one.. Paul

[scott h]

you might want to consider installing a heat shield between the master cylinders and the headers, you shouls aslo wrap or insulate the lines near the headers

[dirtydog427]

Today I took it out again after adjusting the bias to put max frount brake on and changing the fluid.. the car did well but we had a cold frount come in and it was 20 degrees cooler today.. I was out for about 75 miles and as I got more confidence I tried to make em boil and go away toward the end of the run.. and as I got back to the house the very last 1/4 mile they started to drag in the rear.. I usually run it out of gas at the end by turning off the fuel pump and letting it die outside the garage and then push it in..I had felt the addded drag as I got close to the garage and sure enough after I shut it off -I couldn't push it into the garage..I had to let it cool for about 30-45 minutes before it would roll easily.. I also noted I heard a lot of squeaking during the run at slow speeds coming to a stop and starting up again.. from the rear definitely.. This is coming from the Jag Rear End ??This has a line lock on the floor for the rear brakes and I don't know anthing about it. I have never be able to get it to do anything.. It is supposed to serve as an Emergency Brake..Thanks again guys.. Paul

[spd4me]

My 289 has one of those line lock emergency brake buttons next to the seat. When I move the seat up it really gets pinched. Never have used it or tried to. Heard some people say theirs locked up. Now carry a 2 x 4 emergency brake board. Need to cover your brake lines with the thermo insulation at least from the maste cylinder to the brake lite switch. Mine will squek alittle when coming to a slow stop. Probably just dirt and dust on the rotors. If you read other threads, it's very hard to make these brakes lock up the tires. I woud think that the weakest point is the mini master cylinders. The Wilwood calipers and rotors are the best quality. Look at a lot of race cars and most don't use vacumn booster kits. But they do bleed their brakes several times during a weekend event.
Bob

[spd4me]

One other thing I've thought about is placing the front brake line to the master cylinder on the right side of the pedal and the rear on the left. Because of the location of the pedals in the foot box, when you apply the brakes your foot hits the right side of the pedal and pushes on an angle towards the left. So your exerting more force on the right side which should be towards the front brakes. When I drive, I try to apply the brake pedal in more of a push it straight down and not on an angle. Wounder if this makes sence and if so, why Unique doesn't swap the front and rear lines.
Bob

[weaver]

Who are you dirtydog?

[Wareagle]

Had a similar problem a couple of weeks ago but without alot of heavy braking. It has been years since brake fluid was changed and I will do so over the weekend. Was in the 100 degree range here in Alabama at the time. Had the mushy first pump in the clutch and then the brakes. Wrapped the lines in a wet towel ( not a good perminent fix but a get by)and did not experience it again.

Back when we used to get on the track for hot laps, I would pull the pads off after returning home and run them over with a Dual Action Sander and about 120 grit to brake the glaze. Probably not a good long term approach either but kept down the squeal due to slicked over pads. Allen knows alot more about brakes than most of us. My brake bias was never right until he adjusted it.

As for the little E brake valve, I had mine to freeze up on me once and don't use it any more. Probably if we drove the car alot and used the valve alot would not be a problem.

[scott h]

the line lock could be the problem. mine would build up pressure with each use of the pedal until it practically would stop the car, had to crack open the rear brake line and let it leak fluid just to get home. i got rid of it you really do not need an e-brake if you park properly, you can also get a tradtional cable e-brake like me and lots of others have done. would bet money the line lock is to blame.

[dirtydog427]

I am Paul Kaiser from Dallas.. I bought the Jim Dean car back in 96.. The oil pressure started dropping between shifts around 1999; so I let it sit up (how stupid was that !) and the rats got it and just lately have gotten in back together..Dean lived in Parker Co or at least his bank was there or Litttleton Co. It was a Delux Pallet car with upgrade frount end..U all shipped to Co. Dean had it built up in Evergreen by Walt Haynes who used to race Mustangs and was the SCCA champ one year back in the Shelby days.. I just bought a radiator and turn signal and stuff from U guys last month..

So thanks for all the help Unique owners..I had really forgot about that line lock as a problen till Wed ..I will let U all know as I discover what's going on..How do U operate that line lock. Pull up to engage.. I think Allan told me but I forgot..

[arrowdriver]

My line lock on the rear system also started acting like a check valve in that it kept the rear brakes on. I noticed this by the smell of hot brakes, naturally when I was out in the country but by cracking the line connection was able to get back home ok. Then pulled the line lock apart and found that the rubber seal in it had come apart so part of it was plugging the outlet. Removed the rubber stuff and put it back in to make the line connection. Natually it doesn't work as a parking brake but I never used it like that anyhow.

My car was built in 89 and three years ago when I bought it I went through stuff that I figured might have suffered from age including getting overhaul kits for all the Gerling master cylinders including the clutch. The old rubbers were not in good shape. If yours are as old as mine were you really don't want to depend on them without overhauling. My brakes work fine now though I have a heavier foot than some.

By the way, how did any of you add the mechanical hand brake?

[dirtydog427]

Thanks arrowdriver , that's interesting about the rubber deteriation.. I thought when I first got the car back to texas in 96 and looked the fluid and saw all the junk that collects around the caps and inside the caps, "How could this M/C look so crappy and it wass only 2 years old at the time I think .. they told me or claimed it only had 400-500 miles on the car.. It was like there was some corrosion going on between the gasket and the cap?? RUST colored crud..I was wondering what kind of metal do they make in England? Hah-- I guess I can get that stuff from Girling?

I TOO WOULD LOVE TO FIND OUT ABOUT A CABLE SYSTEM EMER/BRAKE (with one of the pretty chrome handles like the old cobras had) AS I THINK I NEED ONE IN TEX TO GET A SAFETY INSP STICKER..AND HORN..WHAT KIND OF HORN DID U GUYS INSTALL? The corvettes have a small brake shoe that expands against the inside oof the rotor..but that would not work here..
ON MY CAR THE FROUNT BRAKE LINE IS on the right side and rear brake on the left side of the pedal...and I know these line need to be heat shielded up frount by the headers..The whole area under the hood is intensely hot.. I need a turkey pan or something to let the engine breathe some outside air.. After mine gets hot it loses about 25-40 HP..U can feel it.. This is a stock sideoiler with the standard cam. and about 10-1 compression.400HP .the oil temp has never exceded 175 or so and same with the H20 after the new al radiator..except when idleing..but it's still making the paint wavy on top the fenders above the headers on both sides..It's way too hot under that hood..

[arrowdriver]

I got my overhaul kits from a local supplier of British collector car parts. The sizes of each cylinder are cast into the outside. American designed master cylinders have a very simple design with just a piston running past a hole in the side of the cylinder but I guess this is too easy for the Brits so they designed a much more complicated piston design that eliminated the side port of the bore. It works fine but no better than the simpler one. These bodies are aluminum so are likely to be vulnerable to corrosion if you are near the coast etc. In my case they were like new.

The balance bar system of proportioning front to back works fine too and is easy to adjust though not while you are driving. All you do is turn the threaded shaft which moves the pivot ball from side to side. How you push on the pedal has nothing to do with the proportion of front to rear braking, this is all dependent on where the pivot is in the tube in the pedal.

[spd4me]

Arrowdriver - try using the search tab to look up emergency brakes. Someone posted a bunch of pics of how they did theres. I got all my parts from Unique but haven't installed. If you've never seen them, Theres 2 pads that hook to the top of rotors connected with a cable that goes to the handle.

[spd4me]

Just found some photos. Search under "ebrake caliper". Go down to "parking brake"

[arrowdriver]

Thanks, appreciate the help. I've seen these in Jags but figure installing this system in my Cobra with all the power train in is going to be a less than fun job. Maybe I'll just park with the car in gear for a while longer.