Quick brake question

[Bamamav]

Refresh my memory....is there a push rod or anything like that that goes between the master and the booster? I gravity bled until I got fluid at the wheels, now i can't get any pressure from the pedal. I took the master off and the rod in the booster is moving out but it doesn't seem like it is coming out far enough. I even raised the pedal for more travel but its still not enough. I have the Speedway universal hanging pedal with the dual booster and the Tm master cylinder. In thinking I am missing a piece.

 

[Old Iron]

Yes there is a pushrod between the booster n master cylinder

 

[Bamamav]

Well I guess I'm missing that piece. I will have to make something work k then. Thanks

 

[Old Iron]

The pushrod for a power brake setup is in the end of the booster but, make sure you have a master cylinder for power brakes as they have two different depths of receiver holes.
The power master cylinder is nothing more than a dimple in the master cylinder plunger and the manual master plunger has a deep hole for the rod to go into

 

[Old Iron]

Here ya go Bam

 

[Old Iron]

The different master cylinders

 

[Bamamav]

Old Iron, on my booster, the rod end is inside the depression on the end, and the end is about where the end of the seal is, if that makes any sense.
Just inside the double end on the spring in your pic. It does not protrude outside of the depression in the housing.

I'm gonna pull the master off in a little while and look at it again. I'm not sure how deep the dimple is on it. I'll take pics of both pieces and post them so you can see what I'm working with.

Right now, it's supper time!

 

[kenny c]

Mav; measure the the amount of protrusion of the rod out of the booster and the depth of the dimple or recess in the master there should be play but not very much, almost none. on some boosters the rod that pushes the master is adjustable. hope this helps.

 

[Bamamav]

OK, I pulled the master and here's what I found:


Here's how deep the plunger is, about 1/4" deep from being flush


Now here's the real kicker, the master cylinder:

 

[Bamamav]

These two adjustable rods came with the kit I assume to set the pedal height:



The distance from the threaded end to the nut is about how deep the hole in the master pushrod is.

I'm thinking I could shorten one of the adjustable rods and bore the hole out so it would fit over the booster rod, with the other end resting in the dimple on the master. Would that work? Maybe I would need to make some kind of spacer to center the rod in the master's bore.

 

[Yankee Transplant]

Old Iron , wouldnt this be the wrong master . if its a power booster its supposed to have the dimple not the hole .. Right ? Or did I miss-read something ? Im curious because I have brake issues myself [S

 

[kenny c]

Mav it appears that the adjustment oh the booster push rod is all the way in at it's shortest point you may be able to adjust it out so that it almost touches. make sure if you do that there is adequate thread left to keep it in place once adjusted.

 

[Yankee Transplant]

Hey , what was the name of the place that sells the late model spindles that will fit the 55 chevy straight axle , Im not trying to steel your thread mav. but I want to go with caliper brakes .. I cant get mine figured out So maybe ill up-grade them.

 

[Old Iron]

Bam, YT is right, you have the wrong master cylinder. You need the one with the dimple.
The master cylinder you have is for manual brakes and the rods are for a manual master cylinder.

 

[Old Iron]

Hey , what was the name of the place that sells the late model spindles that will fit the 55 chevy straight axle , Im not trying to steel your thread mav. but I want to go with caliper brakes .. I cant get mine figured out So maybe ill up-grade them.

RPM has them.
Ron Pope Motorsports
http://shop.eztbucket.com/

 

[Old Iron]

By the way don't adjust the rod coming out of the booster or the master cylinder plunger will not return all the way back to it's seat.

 

[Dirtyrat]

Looking at the pics, I agree, looks like its mismatched and will not get you in a range that will operate safely?

I wonder if there are any other differences on the MC however other than the depth of the bore where the rod pushes the piston? Perhaps a spacer with a dimple tack welded in would yield the correct location of contact between the rod and the MC to get you by until you sort out another MC?

 

[Bamamav]

I knew something was wrong, just couldn't figure out what until I took those pics and studied it. I looked in the Speedway catalog, and they don't list manual vs power on that style master, so I guess it's universal.

Looks like I will be fabbing up a rod to go in the middle. As long as it will float in the master and not stick, and transfer the motion from the booster to the master, I don't see any reason why it won't work. I'm thinking maybe some washers to keep it centered, drill one end to fit over the booster rod and round the other to ride in the master dimple should do it.

 

[Old Iron]

Make yourself a dimple disc out of 14 gauge steel that will fit the diameter of the end of the master cylinder.
While holding the plunger with your thumb, take the ring keeper out, install the dimpled disc over the end of the plunger then put the keeper ring back in. You can do this without have to bleed the system again.
Don't use the rods to take up the slack.

 

[Old Iron]

16 gauge would even be better as it is thinner.