T-Series Still No Luck With Clutch Bleed

[RickTM]

1960 MGA. New master, new clutch slave, new hoses. Brakes bled fine. Pulled two cups full of fluid from clutch bleeder with MytiVac this morning. Hard to tell but doesnt appear to be air bubbles in fluid. STILL NO PEDAL!!!. Maybe a slight resistance on first push then nothing. This is driving me crazy. Any help or suggestions much appreciated. Rick

 

[DrEntropy]

This may sound a bit dumb, but humor me...

A couple questions: Is the bleed screw the top-most fitting on the slave? Sometimes the slave cylinders are shipped with the bleed nipple in the wrong hole. Did ya bench bleed the master?

And I'd be pushing fluid either via pedal assistant or an Eezi-Bleed rather than pulling it from the bottom.

 

[bob67bgt]

Have you got free play adjusted into the push rod. If the piston does not fully return the fluid hole in the master may be partly blocked. Is the master new or rebuilt /sleeved by someone? Bob

 

[David_DuBois]

Use an EZ-bleed and bleed from the bottom. Hook th eEZ bleed to the bleed screw on the slave cylinder and let it push the fluid up into the master cylinder. Another method to do this is run a hose from the right front brake caliper to the bleed screw on the clutch slave cylinder. Open both bleed screws and pump the brake pedal carefully, watching the level in both the brake and clutch cylinders.
Cheers,

 

[RickTM]

OK I think I have finally figured this out. The master is a new Lockheed but it sat in the box a couple of years before I installed it. Today I took off the master and checked it on the bench. After one push the piston was not returning. It would stick in IN position. I completly disassembled the master and plan to order a rebuild kit with new cups etc. Might run a hone in briefly. Hopefully this will solve my problem. And yes I was pulling the fluid from the slave with a vac pump. Know pressure bleed is better but this is all I had. Any other suggestions? Rick

 

[davester]

In my experience, vacuum bleeding doesn't really work without lots of redos and heartburn. Pressure bleed is the only way to go.

 

[RickTM]

Update. Took master apart and found a good bit of what appears to be casting slag in the reservoir. The small openings were completely plugged. This was a new? or maybe rebuilt cyl from Moss that I took out of the box several years ago. It came with a load of new parts and Moss receipts I got when I bought a completely torn down project. Since installed, it has never been out of the garage and never had anything but new silicon fluid. Hope cleanup and rebuild kit will solve this problem so I can get on to the next.

 

[bob67bgt]

I have heard stories about MGA masters that needed a thicker gasket for the front cover when using silicon fluid. The gasket should be relieved so the piston can come out of the bore a little further. I heard that the silicon fluid did something to the seals and they would foul the fluid return hole comming down from the top of the cylinder. Now keep in mind that this is what I have heard and not what I know to be true. I do not normally post things if I am not pretty sure so thats why the owner beware clause! Something else to check.. See where you seal is sitting compared to the hole! Bob

 

[RickTM]

I have spent a lot of time on Barney Gaylord's site The MGA GURU. Barney has a long dissertation on all the brake fluid options and the differences. He says he puts nothing but silicon in his MGA because it is compatable with everything. Also wont harm your paint.

 

[Deleted member 8987]

I have spent a lot of time on Barney Gaylord's site The MGA GURU. Barney has a long dissertation on all the brake fluid options and the differences. <span style="color: #FF0000">He says he puts nothing but silicon in his MGA because it is compatable with everything.</span> Also wont harm your paint.

Compatible with everything?

 

[DrEntropy]

Tell it to Rolls-Royce. :wink:

 

[GeeBee1]

Duck

Pat

 

[PAUL161]

Just another input, for what it's worth, I pressure fill my empty brake systems through the bleed screws, starting with the furtherest one from the MC and work forward and all the air is pushed out. Just have someone watch the MC so excess fluid can be siphoned out. I do the clutch system the same way. I also use silicone fluid, <span style="font-weight: bold">but only in a new or clean </span><span style="font-weight: bold">system where all the DOT-3/4 has been washed out.</span> No, they don't mix!

 

[johnea]

A trick that worked for me on several cars: remove the screws holding the slave cylinder to the bell housing and tilt it to get the bleeder nipple at the top thus sending the air towards the nipple. A second operator should pump the pedal until all the airbubbles disappear. Tighten the nipple when the pedal is fully depressed and you're done.

 

[RickTM]

As a clarification, I did not mean that silicon was compatible with other fluids, I meant that it was compatible with rubber seals etc. My system was all new when filled.

 

[trrdster2000]

Hi all, just one little trick I have been using for 40 years, works on all clutch systems but really well on MG. Push the slave cylinder completely to the rear with a screwdriver or what works for you. Then start your bleeding process, you have a lot less air space and you will feel the piston moving in short order, now insert the push rod and slowly let the fluid push you to the end of the cylinder. You can use the push rod to get it back, but it won't go all the way on some models.

Wayne