help with brake bleed

[T77911S]

the problem is, well 2 problems, my MC is LOWER than the calipers and the MC's have rectangle caps so my power bleeder wont work.
right now my solution is I have ordered an extra cap and will drill a hole in it to either adapt the power bleeder or as I did back in the 90's with my 914-6 put a Schrader valve in the cap and regulate my air down and use my air compressor.

but in the mean time, does anyone have any other ideas.

also have a vacuum bleeder but that does not really work as I cant get a good seal on the little bleeder valve. seems like they are worse with the vac bleeder.

BUT, I thought the vacuum bleeder would work with pumping the brakes because part of the problem is the fluid drains back down before I can get the bleeder closed, but holding the hose above the caliper keeps fluid on the top of the bleeder, but that does not work.

the lines have a bend in them that is higher than the caliper, so I left the calipers sitting up hi over night so any air could maybe work its way to the caliper, no luck.

when I do bleed the brakes with a clear hose attached I see some air come out then its a solid fluid stream and I think they are good. but still very little brakes unless I pump them up.


this is a dual MC system on a race car so 2 separate MC's

[asphaltgambler]

You didn't say why you are into the hyd system. What did you service or replace? It matters as to where the air pockets originate. I would recommend starting with the master cylinder. I would bleed it first which will require another person to help.

Also make sure the brake pedal / leverages full stroke ( in the master cylinder) and that there is some free play on the push rod and the pedal lever when at rest.

Most of the issues with air in the system start with mis-adjustments of the above components even in stock applications or failure to properly bleed the master first.

[T77911S]

its race car.
I replaced all MC's, pulled the pistons out of all calipers and cleaned them, the car has been sitting for over 10 yrs.

wilwood MC's .

there is free play.
car came from my father in law and he said they are a "B" to bleed and I think he made something for the old MC's to bleed them.

[T77911S]

[1990C4S]

Build a pressure bleeder, 5 psi on the MC. Garden sprayer, regulator, whatever.

Drill and tap the MC cap 1/8" NPT, then plug it later.

[Porchdog]

Sometimes the vacuum bleeding works better than the pressure bleeding.

When vacuum bleeding I like to put some heavy grease one the threads of the bleeder screws.

[fastfredracing]

Brakes are for wimps

[Noah930]

Rotisserie? Turn the car upside down so the MC is higher than the calipers?

I would have tried the first two methods you mentioned: power bleeder (don't they come with an assortment of caps?) or hand-held vaccum bleeder. If the vacuum bleeder is leaking, would a new cheapo one from Harbor Freight tide you over until you get that replacement cap for the power bleeder? Or, find an assistant to work the brake pedal.

[nota]

did you bench bleed the new masters BEFORE hooking them up to the lines ?

can you jack up the end/side you are not bleeding to get the MC higher then the slave's

try the beer bottle method to gravity bleed ?

[T77911S]

Originally Posted by Noah930

Rotisserie? Turn the car upside down so the MC is higher than the calipers?

I would have tried the first two methods you mentioned: power bleeder (don't they come with an assortment of caps?) or hand-held vaccum bleeder. If the vacuum bleeder is leaking, would a new cheapo one from Harbor Freight tide you over until you get that replacement cap for the power bleeder? Or, find an assistant to work the brake pedal.

cant you tell, I already have the back end up as hi as I can get it in the pic...

waiting on new cap to drill it out. the caps have a rubber lining or gasket in the top that I will have to also cut, so don't want to do that to the one I will leave on the car.

lesson learned, use cheap brake fluid to get them bled then suck it out of reservoir and replace with the good stuff.

get the gears changed and brakes done and back on the track.

[speeder]

Originally Posted by T77911S

its race car.
I replaced all MC's, pulled the pistons out of all calipers and cleaned them, the car has been sitting for over 10 yrs.

wilwood MC's .

there is free play.
car came from my father in law and he said they are a "B" to bleed and I think he made something for the old MC's to bleed them.

How many master cylinders does it have?

Originally Posted by T77911S

cant you tell, I already have the back end up as hi as I can get it in the pic...

waiting on new cap to drill it out. the caps have a rubber lining or gasket in the top that I will have to also cut, so don't want to do that to the one I will leave on the car.

lesson learned, use cheap brake fluid to get them bled then suck it out of reservoir and replace with the good stuff.

get the gears changed and brakes done and back on the track.

Having cheap brake fluid in the lines and calipers and "good stuff" in the reservoir is the same as having cheap stuff everywhere. The fluid in the res stays in the res, (unless there is a leak somewhere), and the fluid in the lines and calipers is what boils when brakes overheat w inadequate fluid in them.

[T77911S]

2 MC's

yes,
my thought was to use the cheaper fluid to get the air out, then remove the cheap stuff, put in the good stuff and then bleed until the cheap stuff is gone.

[svandamme]

Why bother with power bleeders?
Just do it the old school way.

Put a correct size tube on the brake nippel
snake the tube upwards
open the nippel
pump pump pump
keep the reservoir filled
Air goes up in the tube
when you have enough of a flush
close the nippel

move on to the next one.


All you have to do is make sure the tube fits the nippel
and point it straight up so the air rises.

perfect bleed every time
No helpers needed, no compressor needed, no tools other then tube and nippel wrench.

[T77911S]

that's what I originally did. thought it had a "eureka" idea. but I think the motion of the fluid going in and out put tiny air bubbles in the fluid. although I may try it again.

the pressure bleed did not work. it blew fluid out from under the cap, IE the cap did not seal well enough to the MC body, the cap is one of those with a spring clip.

so, I put the boy in the car, the wife had the hand vac and did the bleeding. she pulled a vacuum, and the boy pumped the brakes and I would open the nipple. kind of old school but with vacuum.

the brake pedal felt better as in pumping did make it better, but I still don't think I have the brakes I need. I drove it down the street, (yes race car) but just went a very short distance as a few cars passed me, but the brakes did not feel that good.

I am tempted to take it to a brake shop and let them deal with it.

it could now be a pad issue. the car sat for over 10yrs, the rotors had some minor rust but when I pulled the pads they did not look that good. I was hoping I could get the brakes working enough so the pads would get cleaned off enough to get a feel for the brakes and the bias so I could order pads.

next I need to fix a running hot issue. I was told it had a T stat for cooling but either It doesn't and it has a restrictor or its stuck. it runs about 230 but the oil temp gets really hi, about 250.

[svandamme]

if it's that old you really have to flush out all the lines.. at which point the new fluid will just push out all bubbles through the tube... No way you can get bubbles going back in if you flush it plenty.

if it's still no good, then you probably need to start checking and replacing the MC.
Even with crappy pads, the pedal should firm up

[cstreit]

There is a universal adaptor for Motive products like this. It’s a flat plate, rubber seal, and some clamps or bungees iirc.