Bleeding problems

[clamper]

I have just replaced all four wheel cylinders (T has been parked for about ten years or more). Now I can't get them to bleed. The rears still had fluid to them prior to new cylinders, the fronts showed no sign of fluid. I filled the master cylinder and tried to bleed, first I opened all bleeders and let it set with the master cylinder full, after couple of hours I closed all bleeders (no sign of fluid). The wife and I started to bleed one wheel at a time, still could not get any fluid to the wheel cylinders. The master cylinder is a corvair and is mounted up behind the dash. Anyone have any ideas???

 

[rooster57]

Bleed the MC first check to see if you have a bit of play in the pedal. This will tell you the pushrod is returning and letting the MC piston open all the way

 

[clamper]

The master cylinder is what I was afraid of, it is mounted in a position that is nearly impossible to get to. I will try to bleed it in the vehicle.
Hopefully that will take care of the problem.

 

[putz]

Try and open the bleeder push the pedal to the floor then close bleeder.The air is probably compressing and not pushing fluid. Do this till you get fluid in cylinders then bleed normally.

 

[speedkills502]

I would second PTUZ if the master is hard to get to, do one wheel at a time till you get fluid to them all and once you have fluid it should bleed normal. It takes to people but I have used this method with great results.

 

[mr27t]

Like everyone is saying, ya's got an air bubble in the M/C. You could use a Vacuum bleeder at the wheel cylinders to pull it through. Some Parts houses, Chuck's-Kragen, Napa, Autozone have day rental tool kits, I know at Kragen in my area it's only $5.00 a day. Give them a call if you don't have a bleeder vacuum pump. If you get a bleeder vacuum pump to use, crack the brake bleeder loose and leave it finger tight and drop a small glob of grease around the bleeder, put on the vacuum bleeder hose... pump it up to about 20 in. vacuum (Inches Mercury) and then open the bleeder. Try not to let the bleeder drop below 5-10 Vac. and don't over fill the pump cup.

 

[T4TWO]

Like other before me have said. If you can take the M/C out and bench bleed it first that will help you with bleeding the rest of the system. Just my 2 cents.

 

[Ted Brown]

Just take a fitting lose anywhere before any wheel cyl, to see if you are getting fluid out when you press on the brake pedal. if so, hold pedal down while hooking the line back up, have your Wife work the pedal for you, or a friend.. at least you will now know if the master is working, and like other's have mentioned, make sure you have a small amount of brake pedal play. and NEVER let the master run out of fluid, or you have to start all over again, from scratch...

 

[Hotrod46]

Clamper

If the car has been sitting that long, you need to pull the MC and verify that it's good and clean. If it was empty, then you really don't know what kind of shape the cups or seals are in.

Sounds like it's under the dash. If so, I would hate for you to get the brakes working and then have the MC start leaking fluid in your interior or (much worse) fail. Then you'll just have to go through all this again.

I would pull it and replace it, just for good measure. The new unit should last for years and you'll be done with it.

Probably not what you want to hear, but hey it's your brakes we're talking about.

Mike

 

[clamper]

Thought about it all night, and Mike you are right. I changed all the wheel cylinders because I didn't trust them. I'm going to play it safe and get in there and pull the M/C and change it. This is the last thing I need to get done before I test drive her for the first time, I just need to slow down and make sure its done right the first time. Thanks for all the help.

 

[Hotrod46]

I just need to slow down and make sure its done right the first time.

Spoken like a TRUE hot rodder!:dummy:

Good luck!

Mike

 

[clamper]

O.k., I finally got the master cylinder out. It is from a 1960 corvair, the pedal is intergrated into the master cylinder. Now I'm having trouble finding a replacement or rebuild kit. Most kits are not for this M/C. Anyone have a good source for corvair parts????

 

[LKE]

Anyone have a good source for corvair parts????

Clark's Corvair Parts - Clark's Corvair - Clarks Corvair Parts

 

[Todd]

Don't be afraid to weigh the cost of doing an upgrade against the cost to repair/replace the corvair piece.

 

[bobscogin]

The wife and I started to bleed one wheel at a time, still could not get any fluid to the wheel cylinders. The master cylinder is a corvair and is mounted up behind the dash. Anyone have any ideas???

Have you verified that the port leading from the reservoir into the bore is not obstructed? Sounds like your master cylinder is the highest part of your braking system. If so, then you should be able to open the wheel cyinders one at a time and simply gravity bleed the system.

Bob

 

[clamper]

Thought about upgrading but next year the body will come off for paint, that will be the time for the upgrades. So for 20 bucks I got a rebuild kit. When I broke it down there was a lot of crap in the master cylinder. Cleaned it up and checked everything, looks good, installed the rebuild kit and I'm waiting to bleed it on the vise prior to installing it this weekend. To pull it out I had to take the dash out, so while it was out I ordered new gauges to replace the ones not working properly, should be here within a couple of days. Another couple of days of work and I should get to test drive her for the first time. Can't wait!

I want to thank everyone for their inputs, it was a lot of help.

 

[blownt]

have your m/c bolted to the frame bracket with the plunger rod , clevis and brake pedal all hooked up. If you have the brake lines already plumbed just undo the connections to the m/c.

Not sure what size your m/c outlets are? Mine were both 3/8"-24 which is the same as a fine thread 3/8" bolt. You might have one 1/2"-20 which is the same as a 1/2" fine thread bolt.

Thread a 3/8" and 1/2" fine thread bolt into the bosses on the m/c and bottom them out plugging the holes. Fill the reservoirs nearly full with brake fluid. Now push the brake pedal ONE TIME. Wait 15 seconds and repeat ONE PUSH. You will prolly do this many times before you finally get a hard pedal.

Remove one of the bolts and reinstall the brake line then remove the other bolt and install the other brake line. Now bleed all four wheels starting with the right front, left front, the right rear and left rear. Make sure the reservoirs stay full with fluid as you bleed the brakes.

Once you have bench bleed the m/c correctly you will see that bleeding the four wheels are very easy. I always had a bear of a time bleeding the four corners and getting a firm pedal but this last time it was so unbelivably easy it was amazing. I was done in less then 10 minutes. And I have to attribute that to 15 years of never having the m/c bench bled correctly. I always hesr so many people here having the same problems bleeding the brakes on a bucket but now I believe I have found the reason. Atleast I have for me.

 

[joes23t]

Clamper: Also don't be surprised if even after you bleed the MC on the bench and install the MC that you dont get fluid to the brakes . If this is the case loosen the brake Flex line one at a time and see if fluid is passing if not the line could be closed up due to swelling, old age or some one pinching it closed in the past with the old vise grips to service them.I have had this problem in the past. Just a thought Joe

 

[clamper]

I used a modified version of BlownT's method and it seems to have worked. Other Priorities have come up (Daughters wedding) and I'll get back to finishing after the wedding. I want to thank everyone for all the help. :biggrin:

 

[Track T-4]

Clamper,

Did you totally resolve your brake problem?

I'm having a similar problem. I bench bled the master cylinder then installed it and hooked up everything. Have bled and rebled all four brake cylinders several times but it still takes two pumps of the pedal - the second is a solid pedal. Also let it set for a couple of hours and rebled the brake cylinders but cannot do better than a two-pump pedal. I also tried jacking up the front end because I heard the air could get trapped if the brake cylinders are lower higher than the m/c....to no avail. Anyone have any suggestions?