More Brake Questions

[Jeff Scoville]

Or are you missing the spring and retainer altogether?
If it were just tight on the pedal, you ought to be able to open that up.
Either way, try putting in a spring to help return pedal to up position, this should solve the problem regardless.

 

[mikephillips]

One of the things I've noticed over the years is that the length of the pushrod, inside the retaining washer, is different from year to year. Some have a stub on the end and a deeper dish in the piston that others. I wonder if that's what's he's saying, that the pushrod doesn't fit with the VB cylinder. A longer pushrod with a cylinder with a shallow dish in the end would cause the piston to not fully retract since the pushrod would stop it short of the end of the cylinder.

 

[burgy711]

Its the U shaped end isn't wide enough for the peddle. I used some heat and widened the U to fit the peddle but the push rod seems to be just a bit long and isn't getting fully extended to the point where the internal cylinder will allow back flow. I can remove all from the peddle and it will work. Suppose I could alter the holes in the U part of the push rod to allow another 1/8 of an inch play but I think I'm right at the back side of the U anyway.....

I have the springs and retainer. That is not the issue. It is that when fastened to the peddle the piston is not fully retracting. Suppose I could cut and re-weld on the pushrod but that seems extreme.......

 

[mikephillips]

How deep is the pedal attachment U?? Is the pedal hitting the top before it fully retracts?? If it works when the pedal isn't attached and there's nothing in the original setup to prevent pedal movment up to hitting the underside behind the dash the only thing I can think of would be if the U was too shallow.

 

[burgy711]

Originally yes - I would agree with you that the U is or was too shallow. But the reality is that the U was actually to narrow to fit the peddle without spreading the U out further. That was what was done originally when I put the car back together. I believe - though not 100% sure because it was in a three year restoration and somethings I don't remember - that I bought this Master Cylinder a couple years back from VB (SS was out of stock) and the brake lines and master were the first items I put back on the car. Over the weekend it became obvious that the plunger wasn't fully backing out the cylinder and that was prohibiting the line to back feed the pressure back into the master cylinder. I used heat and some bar stock to "adjust" the U so that it would accept the entire peddle. When refitted to the car without the brake peddle it worked with air being able to back feed into the master. Re-fit the peddle and it seems to just enough engagement to cause the piston to block the master from being able to back feed. And, with the adjustment to the U I'm pretty sure I'm at the back side of the U and right to the peddle. I don't think if I adjust the holes in the U that get pinned to the peddle that I can create the 1/8th of an inch that it seems like I need. SS is OOS B/O on new master cylinders so, I'm thinking maybe its a cut and a small weld on the plunger??? Just kind of scares me.......

 

[burgy711]

I think I have a solution that came to me today....... if I move the master off the firewall about an 1/8 or 1/4 of an inch I think I will create the needed room for the plunger to fully extend............ I'm excited. I think I have a solution.

 

[RootesRooter]

You must have more problems than just the "U" being too narrow. I removed the firewall spacer on the brake master to make room for Webers and still have available pedal travel.

If you get that master out of your car again, see if there's a part number on it that someone on the board with a parts cross-reference guide can look up.

I think I have a solution that came to me today....... if I move the master off the firewall about an 1/8 or 1/4 of an inch I think I will create the needed room for the plunger to fully extend............ I'm excited. I think I have a solution.

 

[burgy711]

I don't have a firewall spacer on my master. My master is bolted directly to the firewall. It's the plunger that is just a tad too long. Maybe if I had the spacer???? The gas peddle return spring is very close to the brake peddle but I don't think it is a real problem. I've looked to try and reroute the spring but don't see another option. Might have to create my own spring option.

Only part number I've seen is Girling 70 on the unit.

 

[Bill Blue]

Steve, there is supposed to be a spacer, but most seem to be able to get by without it it. You state the rod is too, long, indicating the brake peddle hits a stop on return. Is the brake peddle returning to the same height as the clutch peddle? It should.

The accelerator spring should not be a problem.

Bill

 

[burgy711]

Sounds like I'm missing the spacer and that is my 1/8th of an inch that I seem to be needing. Yes, the brake peddle is to the clutch peddle. In fact the brake peddle extends maybe an inch further than the clutch. Sounds like I just need to make up a spacer and get the 1/8th inch I need...... Viagra for the brake master cylinder plunge rod if you will.......

 

[RootesRooter]

Sounds like adding a spacer should do the trick. Just wondering: Did you by any chance connect the masters to the pedals so as to push them towards the driver as far as possible? If so, moving to the other hole on the brake pedal arm might give you the tiny bit of extra travel you need even without the spacer.

 

[burgy711]

I'll give it a try but if I recall the clutch pedal has two holes while the brake only has the one......... are they back wards? Or should both have two holes. I didn't look real hard but I think the pedal only has the one?

 

[Bill Blue]

My brake and clutch pedals are interchangeable. At least I could not see any difference.

Bill

 

[RootesRooter]

Both should have two holes. If yours don't, are your pedal arms identical in shape? I wonder if a PO could have substituted an early Series pedal?

I'll give it a try but if I recall the clutch pedal has two holes while the brake only has the one......... are they back wards? Or should both have two holes. I didn't look real hard but I think the pedal only has the one?

 

[burgy711]

The pedal does have the two holes. I don't think I have enough room in the U on the plunger to use the second hole. I will try today to get this fixed. First I will see if I can use the second hole to get my extension and get the master opening for the pressure relief I need. If not, I will fabricate a spacer to use between the firewall and the master. One or the other will work. I'm confident.

 

[burgy711]

Brakes are working......... HURRAY.

Seems moving the master off the firewall did the trick and the master is now able to take the back flow pressure. So, lets see; one set of new caliper pistons; a new rebuilt brake booster; a master cylinder rebuild kit; eight weeks of frustration....... only to find two washers does the trick..... PRICELESS!

OK in all fairness, the caliper pistons were a big issue and needed to be rebuilt...... but that was six weeks ago ...... argh!

 

[Green67Alpine]

Kinda funny, how large projects get overshadowed by the small things that make them work !

Tom J