Power Brake Booster Help Needed

[BigMike]

Quick recap.

Truck had power front disk conversion when I got it. Brakes always worked great, but the master cylinder leaked. I replaced the master cylinder since it was extremely rusted ($45). The new one still leaked from the lid (front port), even with a tie-wrap on it extremely tight. I traded that one for another new one and that one did the same exact thing. And yes, I bench bled the snot out of all of them.

I got so fed up with the whole thing, especially after ruining the new paint on the inside of the fender under the hood, so I replaced the entire setup (booster, master cylinder, proportioning valve) with this. http://www.ebay.com/itm/Power-brakes-FO ... es&vxp=mtr

The new system worked great and no leaks, but, no matter how much I adjusted the brake rod, the pedal wouldn't come all the way to the top. The ebay guy was great to work with and had the booster replaced under warranty. I got the new one and it worked fine for a very short while and started to do the same thing. There is nothing binding and the brake rod is dead center in the booster and going in and out straight.

I called the manufacturer (http://mbmbrakeboosters.com/) and the guy I talked to in their tech department didn't think the booster was big enough (7" dual diaphram). I contacted the ebay seller who said they've sold a 1000 of these and have never run into this type of problem. He's trying to tell me that the '65 Ford trucks had return springs on the brake pedals which I told him was not correct. I'll deal directly with MBM if I have to but looking for ideas. It is like the the booster is sticking the last 1/8" or 1/4". I'm going to check the vacuum it's pulling which should be about 18".

Anyone have other ideas?

[Shadow]

For What It's Worth, That Looks Identical To The Setup That I Have. Mine Is For The Drum/Drum Application. Did Yours Include The Proportioning Valve? Also The Disc/Drum & Drum/Drum Master Cylinders Look The Same But Are Different. The First Vacuum Booster They Sent Me Was The Wrong Size. The Second One They Sent Me Was The Right Size But Was Missing The Push-Rod. The Third Tried Everything To Get It To Work Before Checking The Vacuum. (Bad Diaphragm) Finally I Was Sent A Decent Working M/C & Booster. After All That It Works Well. All This Being Said, The Fact Is These Are Chinese Made Parts With Poor Quality Control At The Factory. The Good Thing Is The Tech Support I Received And The Company (Performance Online) Working With Me Shipping The New Replacement Parts At No Cost.. As For The Leaking I Didn't Experience That Problem With Mine. I Think If I Were To Ever Do This Again I Would Look For American Made Part At The Junk Yard.. Hope This Helps & Good Luck......

[foodstick]

I wouldn't be afraid of a light return spring if everything else works well?

You should have seen the $100,000 equipment the dairy i worked at.. there were rubber bands all over the place HELPING parts along

[merc uni]

This sounds the same as my 7 1/2 dual dis. Booster. Same make. The last 1/2 - 3/4 " sometimes will not return . No binding,has clearance at pushrod. I can only think that the internal vac. Release valve is flakey. Lost my reciept ,so. I am sort of stuck with it. Put on 2 big return springs and that seems to work. I guess you get what you pay for in the end.

[BigMike]

Thanks for the replies.

I have a spring on there now but it bothers me because it shouldn't need it. I have 18" of vacuum which is how much is needed to operate the booster.

I'm working with management at MBM now to figure it out. I don't care if they have to send me 20 boosters to get one that works right.

[unibody madness]

I totally agree, it seems a shame you have to deal with that.
I simply whent to a pick and pull and managed to get it right, off of a cherokee, Not sure who the manufacturer is but looks fairly generic but my 61s came with a spring.
John

[charliemccraney]

Mine has a return spring. I've pulled a few off of trucks in the junk yard for spares so it's definitely stock.

Oh, crap, nevermind, you said '65. Must be different for the twin I trucks.

[BigMike]

MBM is sending me a new 9" booster and I'll return the 7". I think that there is definitely a leak in the diaphram because 2 minutes after the truck sits with the engine off, there is no vacuum in the booster. That is probably why it worked at first and now doesn't. I hope that the 9" booster isn't too much.

[Shadow]

I Feel For You Bigmike, I Tried To Put A Single Diaphragm In My Truck But It Was To Tight With The Y-block. The 7" Dual Diaphragm Is Specified For The F100- F250. I Had My Truck Stall Going Down A Hill The Other Day And The Pedal Went All The Way To The Floor. Without The Engine Running= No Vacuum I Guess. Scared The Crap Outta Me LOL...