Dragging Brakes w/ Hydroboost

[hucktruck]

My searches for hydroboost problems do not match what I am experiencing so I need some advice.

I have a Ford hydroboost off of a mid-seventies Lincoln and the master cylinder I went with is a Mustang (DISK/DRUM) from the same era. I have Cheby disks in front and drums in back. It works great but drags after I drive just a few miles. I have adjusted the rod and I feel I have a good length on it. I upgraded my cooler from a stock P/S cooler to a Explorer trans cooler and I just bleed and replaced all of the fluid (I’m using P/S fluid).

The hydrobooster seems to be building up pressure and it drags so bad it practically wants to lock up the front. The pedal can barely be depressed to stop when this happens. I can release the pressure from the hydroboost by backing up the bolts on the M/C until the pressure is off and then when I tighten the M/C back down everything is fine and I can drive it again. It works normal after I do this.

I am tired of having to stop to release the pressure off of my hydroboost and M/C to drive again. There must be a solution to fix the backpressure. Maybe I need to rebuild it. Is there a kit or would I need to have it done? I’m at my wits end here.

TIA
Darin

 

[Desert Thrasher]

Check the depth of your MC where the HBoost rod goes in. I had the same issues and needed a spacer about .125 thick. So I made one out of some aluminum plate I had laying around. It works great now and no more dragging/overheating.

 

[hucktruck]

I have a gasket between them now. I made the gasket from a variety packet of gasket materials. I used the black cardboard stuff that I thought would be used in applications like this. So a thicker gasket then or shorten the rod maybe?

 

[Desert Thrasher]

Yea I would try something other than gasket material. It needs to be a solid spacer. Mine needed 1/8". I compared it to an older MC that did work with my H-boost versus the one I was installing.

 

[AWS]

Darin, bring a pattern over to the shop, I've got some 1/16 and 1/8 scraps you can cut up.
Steve

 

[hucktruck]

Steve,
You don't think there's anything wrong with the booster?

I hope this fixes it!

 

[Desert Thrasher]

Did you get a spacer and did it work?

 

[mr.n]

My searches for hydroboost problems do not match what I am experiencing so I need some advice.
There must be a solution to fix the backpressure.

I bet you don't have a Hydroboost pump & reserve.

And thus you've a "T" fitting for your returns? If the flow is wrong you'll get drag. I don't have the pic handy but TOFIC must have it...
The flow from the Sector must be straight through, and the hydroboost should comein at the 90*.

 

[hucktruck]

I do have a dual return pump so I'm okay there.

I'm going have to make a spacer but Steve and I did test the idea on Saturday by using some washers as spacers. The pedal feels different because I don't get the resistance at the top like I was used to but it isn't dragging anymore with the washers in between the booster and the M/C. Since I pieced this system together I'm not surprised my gasket didn't work as planned. That's how I roll. Only now without dragging. Thanks everyone for your help!

Darin

 

[TOFIC]

Now all you have to do is grind down the intermediate rod the thickness of the washers and remount the MC. I do not recommend you run with the washer spacers for long. Reason being your brake pedal and brake pedal leg can exert enough force to bend or break one of the spacered bolts. this is why MC to power boosters have a large bearing surface on them.
My two cents worth (or is it a nickel to allow for inflation!)
TOFIC

 

[72Sport]

Now all you have to do is grind down the intermediate rod the thickness of the washers and remount the MC. I do not recommend you run with the washer spacers for long. Reason being your brake pedal and brake pedal leg can exert enough force to bend or break one of the spacered bolts. this is why MC to power boosters have a large bearing surface on them.
My two cents worth (or is it a nickel to allow for inflation!)
TOFIC

Your are talking Canadian cents. That is about 4 cents U.S. with the value of the dollar taking a crap.