The Stovebolt Site Forums The Shop Area Driveline Brakes locked up

After several years of my 53 sitting in the garage I worked on it to get the engine running. Went to back out and brake pedal would not go down at all. Rolled under truck, squezed the dust boot and fluid came out. Will not plunge at all.
Tried to take cap off MC, 7/8 socket would not turn and kept slipping.
Is first step removing MC and going through first?

yes, the MC will need a kit - and when you do it, replace that cap with a plastic one, they don't seize on

Bill

Using a 6 point socket works the best to get those caps off.

Isn't that a square on the cap? That would be an 8 point socket.

Found the rebuild kit this morning local at Carquest Lexington. ($24) Who has a plactic cap? I do want to replace this one. Whole master cylinders they think a lot of $$$$.

most of the vendors have something, Carter has plastic - I think American Classics is aluminum, which works well with a gasket - most places also have fiber gaskets, but a large rubber O-ring works better

Bill

Couldn't get the brake line unscrewed, had to cut the lines. Having a hard time getting the ends off. Never have done lines before. Can I use the same lines and redo the ends that I cut off?

Probably not. I wouldn't chance it. Brake lines corrode from the inside out and I'll bet yours are pretty crusty. When it comes to brakes I believe in do it once, do it right, do it all. Brakes are too important to leave anything to chance.

Its a good idea to get brake/fuel line wrenches before attempting this. These wrenches are really worth the expense. The metal on the fittings is so soft and easy to round off, its nice to have the extra contact. Be sure to clean out the brass blocks and anything you are not replacing just to ensure its all open.

Didn't know about the wrenches. What makes them different? Got it all apart, looks clean inside. Now need new fittings and redo line ends or redo lines. Is there an exploded image of the master cylinder available? Is there detailed instructions on doing new lines?

Flare nut wrenches are made to make full contact on 5 of the flare nuts 6 sides, allowing to work more like a socket or box end wrench. You should be able to get a good set from the auto parts store or local Sears for a reasonable price. Redoing the lines isn't too hard, you'll need to measure the lines to get the overall length and you'll also need a good double flaring tool. If you've never done double flares before, you might want to get some extra line to practice on. Here's a video I made a while back showing the process.
MAster cylinder diagram.

If you are not concerned with 'factory correct' you can buy pre-cut lines of various lengths at the auto parts store. Most of the bends can be made by hand.

Here is an essay on installing a dual master cylinder in my '56. Also a write up about the flaring tool.

While the specifics won't be right for a '53, the general overview will help you.

I'd recommend going with the dual cylinder 'while you're in there'.

Guys,

Thanks for the help. Cletis, the dual master cylinder in my 56 went to a Frank Zappa Video.

I have a flairing tool that I bought years ago from Harbor Freight, but missing the inserts to do the double flair. Went back today to see about buying just those and they don't still have the kit I bought there anymore. They did have the wrenches though.

Went to my local parts place KOI (Ky, Indiana, Ohio) and bought a compression fitting and a 1ft line with fittings for each size. 3/16 and 1/4. My lines look good and really didn't want to go that deep on this truck right now.

I do have a couple of other trucks that I will be doing complete lines on so I need a good flairing tool. Watched the Eastwood video, sweet but HIGH coin. What's the best for the money?

Also, probably should go to a dual MC on the next ones. 46 & 59 trucks. Do many guys out there go power brakes?

I fixed the link.

I went with power and front discs on the Suburban. I love it.

Do you actually have a compression fitting, or are you meaning a double flare union? Compression fittings (the kind with the brass collars that go on the line) are not legal for use in brake line systems, the only correct way to connect two lines together is with either a double flare (standard size line) or bubble flare (metric line) with the occasional odd hybrid flare (late model GM and Ford).

They sold me a double compression fitting that does not require flairs for both 3/16 and 1/4, along with a foot long line of each size to go from the MC to the old line.

I did find separate flair fitting inserts for my flair tool that didn't come with them to create the double flair. Carqust has them for about 4 bucks each size.

They sold you the wrong fitting, those are not legal for use on brake line. Low pressure lines such as oil or fuel, sure, but never on brake line.

After consideration of all the posts here, I took off the cut lines back to the fittings, measured them and will return the compression fittings tomorrow to buy both lines pre-made with fittings. If it don't run you don't get hurt - don't stop, get hurt!

Thanks Guys

Anybody have a link to a video showing the MC rebuild?

Returned the compressions and bought 51" lines. Needed 46", guess make a big loop at the MC?

Do I use any sealant/locktite on the fittings?

Manual says wash all MC parts with alcohol? Round here thats easy to find, from the hollar. Right John?

Do I need to fill MC with fluid before bolting back on frame?

One of the fittings is on the end and the other is on the back side of the block on the MC, [censored] to get to.

No need for Loctite or sealants, the flare will seal fine without it. Good old brake parts cleaner, which is essentially alcohol, will be fine for cleaning the parts.

Ok, what is going on?

Rebuilt MC, ran new brake lines and bled the lines. The brake pedal is just like it was when I started this thread, hard and will not push in. Now I wonder if I just did all this work for nothing except a good brake lesson.

What can this be?

If the brake pedal won't move how did you bleed the brakes? Did you bench bleed the master cylinder before you installed it on the truck?

It moved to bleed the brakes. Then I put the cap on the MC. If the cap has the vent hole blocked, could that be the problem?

yes, the MC cap does need to be vented on these ancient systems

Bill

OK GUYS,

Made sure the vent hole was open in the MC cap. bled all 4 lines. Pedal goes down just fine when bleeding, refilled MC to top with fluid, replaced cap. Pedal is rock hard and no brakes. If I leave cap off and push on pedal, I see the silver piston move and fluid squirts up from the rear hole. Could it be that the wheel cylinders are locked up? This truck has been in the garage for about 4 years without moving or starting. How is the best/easy way to check wheel cylinders?

if it works with the cap off, and bleeding happens [you actually get fluid out the bleeder], there's nothing wrong with anything, it should work with the cap on, replace the cap

Bill

Made sure the cap was breathing, still hard. Only thing left are the wheel cylinders???

Replace the line don't try to flare the end of an old line if you haven't done this before. As for the line wrenches they look like a six point wrench with a slot cut out on the end for the line to slip thru. Now when you go to remove the other end of the line that you cut here is my suggestion. Get some Kroil or PB Blaster penetrating oil. Soak the fitting a day or two before you try to remove. Lightly tap the fitting as this vibration will help the penetrant work into the threads.

Needed 46" lines for both 3/16 & 1/4. Bought pre-made 51" lines and bent to fit.

bled all the lines, refilled the master cylinder and put on new cap. Brakes still hard and don't depress.

Took off wheel and brake drum. Pressed pedal, still hard.

If all brakes bleed OK and still hard, I figure either the cylinders are locked up or could I have rebuilt the master cylinder wrong? Does having enough pressure to bleed the brakes equal enough pressure to work the shoes?

not a matter of "enough" pressure in a hydraulic system, either is pressure or isn't ..... hard to believe all 4 wheel cylinders would corrode so solid none will move, but if you pressed the brake pedal with a drum off and that cylinder didn't move, at least that cylinder is seized, try it with both drums off each side - push pedal gently/slowly, have someone watching to see if the shoes move, might have been a good idea to put kits in the wheel cylinders while doing the MC

Bill

The reason I did the master cylinder was because of the hard pedal. After rebuilding the MC, running some new brake lines and bleeding the system with my 13 year old Son, this has been a great learning expirence. Probably the MC was OK and was the wheel cylinders all along. I watched a guy on youtube last night change out the wheel cylinders, so thats our next lesson to rebuild them. Right after I check wheel 2,3 & 4.

Took off drum 2, still no movement. Took off wheel cylinder 1 and it was completely locked up. Drove out interior parts, rusted and pited. Might as well order all 4 cylinders and bleeder screws.

Question 1 - Best place to order parts?
Question 2 - Speed Bleeders Y/N

No wonder hard pedal.

new cylinders come with bleeders in, should be available at NAPA or the like, otherwise the vintage vendor of your choice

Bill

Napa was cheapest, around $17 front & $27 rear each - China made

Bleeders were 10mm, not standard.

Carquest was around 31 & 37, may have been made in USA?

If things were not real tight right now, would buy USA.

All 4 of mine were locked up crusty.

May end up with brakes soon, yeah!

you may want to re-figure your finances, I had one of those Chinese NAPA cylinders start leaking after a month, when I went back all they had was the higher priced model, they don't sell the Chinese ones anymore, too many returns

Bill

Front right would not fit so I went to Carquest for the $32 one thinking it would be USA, came out with same China part. So I went back to NAPA and bought the $14 part and ground the backing plate for it to fit.