Brake problems - 60 Bird

[Charles Nix]

I recently had a new master Cylinder installed (old one was leaking into the cabin). After bleeding the system, I have much better braking until the brakes get hot, but once hot, the brake pedal becomes roc hard with no travel and the brake shoes feel like they are dragging. Does anyone have any suggestions where to start to fix this problem? Bad Brake Booster?, Air in the system? Loss of vacuum? Thanks.

[jopizz]

A bad booster, air in the system or loss of vacuum would cause the opposite problem. You would lose pedal. If the brakes feel like they are dragging when hot then it sounds like your brake fluid is overheating and expanding. I would check your brake lines and make sure they are not too close to the exhaust pipes, especially the rubber hose over the rear end. Another possibility is that your drums are warped and it's showing up more when they get hot.

John

[Charles Nix]

Brake problem fixed

Thanks for the advise. After your response, I checked the front wheels when the brakes were hot, and the wheels would hardly turn. I adjusted the shoes and that fixed the problem. The mechanic (?) I asked to bleed the brakes after the Master Cylinder install had them way too tight and the heat buildup was causing the fluid to boil and the brakes to drag. Thanks for your help.

[simplyconnected]

I recently had a new master Cylinder installed...

And therein lies your problem. I know your front brakes were too tight and they needed to be backed off.

But when your foot is off the brake pedal, your master cylinder piston is retracted which opens the brake lines to the reservoir, allowing the shoes to retract. <--think about this because even if a line were too close to an exhaust manifold and the fluid boiled, the fluid should not build pressure (or expand the shoes) but go directly to the reservoir.

Make sure your brake pedal rod is not pushing the master cylinder piston in, at rest. Your pedal has a cam-bolt that adjusts the brake pedal rod.

I don't know if you have a power brake booster under your hood but if you do, there is another adjustment screw on the output side of your booster. I find that not all master cylinders are the same, so this adjustment is equally important as the brake pedal rod.

To see the booster adjustment screw, keep your brake lines on the M/C but unbolt it at the booster. Let the M/C hang for now, and have someone gently push the brake pedal down while you look in the booster; that rod will come out so you can use a wrench to loosen the jam nut.

All this is covered in your Shop Manual. Please read it carefully. Hope this helps. - Dave

[Astrowing]

Also make sure that your brake drums are within spec. The front ones on mine were turned too many times and were way oversize. Braking performance is way better with properly arced shoes and sized drums.

[Charles Nix]

brakes still locking up

Well.................thought I had the problem solved, but not so. Brakes still locking up. Thanks to Dave's explaination, it now makes sense to me that the brake pedal rod must be pushing on the master cylinder piston allowing the brake fluid to apply the brakes (and build up heat) as I roll down the road. I'll get the free travel of the brake pedal rod adjusted and hope that this corrects the problem. I will post again after I get this done......hopefully with good news. Also, my brake booster is up in the dash, so hope no adjustment is needed on it. What a poor design concept by Ford.

[partsetal]

Now that you mention that you have the Kelsey Hayes booster (under the dash) I recall having a similar problem that I spent a lot of time on until I went to the troubleshooting section in the Shop Manual. This booster has a filter, and my filter was clogged, preventing the booster from releasing ofter several brake applications. The shop manual has a diagram showing this filter. It is retained by a clip and you can remove the clip with a right angle probe and use the same probe to fish the filter out. Clean the filter w/solvent and attach the clip to the filter and reinstall, push the clip with a blunt tool to clip it into place.
Carl

[simplyconnected]

...What a poor design concept by Ford.

As Carl pointed out, this brake system was designed and developed by Kelsey-Hayes.

None of the car companies made their own brake systems. Treadle Vac systems were prominent on GM and Packard cars as well. At the time, these brake systems were modern advancements. (Isn't that scary?)

The only saving grace was, nobody had any better and all cars were heavy so all drivers offered much more courtesy on the road.

Purists would rebuild these old vacuum systems. I'm sorry but if your car is competing with today's traffic, it needs to stop a whole lot better than the old system allows. I love to see an original factory-fresh car but those cars need to be in a garage or on a trailer; protected from all harm. All the specifications classic cars were built to and all the fluids they used, have changed dramatically and so has all of modern society.

I drive my classics but they have modern improvements. If the next guy wants to change it back, I won't mind at all. - Dave

[Charles Nix]

adjusting brake push rod

After reading up on how to make the adjustment on the brake push rod, it appears that it's quite an ordeal just to get to the cam bolt. Is it easier to do than the shop manual makes it appear? I'm seriously considering scrapping the stock system and installing power disc brakes because of this. Not sure I want to invest any more time and money into such an antiquated system. Does anyone make a disc brake conversion kit for the Squarebird?

[simplyconnected]

Regardless of the system you use, the brake pedal bolt is always used.

I whole heartedly encourage anyone to retrofit power disk brakes on your Squarebird but it isn't easy. If a brake pedal bolt is too much, you may want to reconsider because these cars came out well before disk brakes. That means you will put a system together and adjust everything from scratch.

I never liked the Treadle Vac system. Rebuilders always talk about the horrible materials that were available back when these units were installed. We rarely see one that works, today. Even so, they are inadequate for drum brakes and totally useless on power disk brakes.

For power disk brakes, your system will need at least a two-stage 8" power booster. We bolt them onto a dual reservoir master cylinder (with an adjustment between the two).

You can do the conversion but it will also include new wheels. - Dave

[YellowRose]

Brake problems - 60 Bird

If you are thinking about converting to Disc Brakes, there is a ton of information available to Paid Members in the Members Conference. I think you would find that it is well worth the $20 for Paid Membership.

[Charles Nix]

Disc brake conversion

Thanks.........will definitely do.

[Charles Nix]

Brake problem finally fixed

It dawned on me this morning that I might be able to get brake rod clearance by shimming the master cylinder away from the fire wall. After putting a 1/8 " thick washer behind each stud and retightening the master cylinder (using self locking nuts), I could feel free travel on the pedal which I didn't have before. Took it out for a long test drive and the problem seems to be fixed. Thank you to everyone who helped me figure out the source of the problem. The level of expertise on this forum is phenominal. Thanks, again!