Right front break locking up...

[7tee]

1970 drum/drum brakes and when I start coming to a stop the RF wheel locks up and slides. I have adjusted the brake shoes in to where the wheel will free spin with little or no drag and today it still would lock.

Question, could the distribution valve be faulty causing more pressure to go to the right front causing the lock up?

A year ago I replaced shoes and master cylinder and all was good. This has just started in last two weeks. Thanks Ed

[Wrenchbender Ret]

It probably is getting grease or brake fluid on the linings. When you replace shoes you must o-haul or replace wheel cylinders. It could be the brake hose is swollen up inside.

[snipescastle2]

Sounds like your brake hose is collapsing, that happens a lot in older hoses.
Ben

[tdangle]

is your left front brake working? I would look at this, since if it isn't working you are trying to stop with only the right front brake. Grease or oil on the RF shoes would keep that side from creating friction to stop as well as a collapsing brake hose.

[7tee]

Sorry but I meant to include that all three hoses were replaced 6-8 months ago. There is no grease or leakage on the right side. Left side has proper drag adjustment and with the truck jacked up, both wheels will not turn by hand...

[old51sedan]

I just had a similar problem with my old car. It would pull to the right every time I stepped on the brakes. Turns out my left wheel cyclinder was froze up. I installed new wheel cylinders on both front wheels and now it works great.

[crakarjax]

My money is on a leaky wheel cylinder -- the fluid will cause the shoe to stick and lock up

[saxart]

My '70 LWB Fleetside did the EXACT same thing when I brought it home 2 months ago. (right front wheel locked up) Anyway, when I redid the brakes, I replaced the front brake hoses. When I was done I cut the hose apart with a side-nippers just to see what it looked like on the inside.

Sure enough... Swelled internally, almost to the point of being impassable.

[7tee]

Ok I pulled the left hub and there again all looked good and was dry. I've ordered new front wheel cylinders and new front hubs being that these haven't been replaced and we'll see how it goes from there.

Can the brake hoses go bad in 6-8 months? Thanks Ed

[GR8-68]

They shouldn't, but there is always that chance of defective. Time to convert to disc's

[mike16]

Originally Posted by GR8-68

They shouldn't, but there is always that chance of defective. Time to convert to disc's

or maybe fix whats wrong

[Mike C]

Discs are mandatory conversion if you want to drive on the road in traffic IMO, but you should be able to get the drums to work satisfactory.

The wheel that is locking up may be working correctly, the one(s) NOT locking up may have issues. Either way, time is money and you should just run through the whole thing IMO.

Rubber lines, wheel cylinders, master and shoes at some point should all be done at the same time. And it sounds like that time may be now.

Also make sure that all of your drums are within spec. Oversized drums can cause braking issues as well. Especially as pads wear and wheel cylinders are asked to move beyond their design parameter spec.

[fwayne]

The great thing about Drums currently is they are dirt cheap to completely overhaul. I replaced everything on my 70 with brand new parts and it cost less than $200 from NAPA. I was even shocked it was all in stock, Drums, springs, hoses, wheel cylinders and all.

Properly installed and adjusted drums are plenty enough to drive around. Heck Drums were still used on the rear of modern tucks through the 2000's and they weight almost twice as much as these older trucks!. Disk conversions done properly are great but not cheap. I can easily brake hard enough to lock the wheels with my drums. Now, if I were daily driving in heavy traffic or Towing, I would say ditch the drums on front and go with the best conversion you can afford but this is due to brake fade, not total stopping power. Otherwise my truck has faired quite well for almost 50 years on drums, it can go a few more.

[Wrenchbender Ret]

Let me get this straight. Both wheels will not turn by hand off the ground. Sounds like the master cyl rod needs adjusting. It may not be letting the piston come back far enough to release the pressure. Or it may be that the pistons are sticking in both front cylinders.
Sometimes you have to champher the top & bottom edges of the linings. The sharp edges have a tendency to dig in.

[7tee]

So I removed the old wheel cylinders and the 6-8 month old rubber hoses and they could still be blown through (so that was good). Now this is what the cylinders looked like so I'll replace them and new drums and I'll see how it works. Thanks for all responses... Ed

[saxart]

For lack of a better response... What the hell is that?

You've got some sort of MAJOR contamination there. It almost looks like there is water in the brake system?

With that that amount of contamination, you probably should figure out where it's coming from before proceeding any further. I'm sorry to say, but something is not "right" there. Unless someone dumped something into the brake fluid reservoir that wasn't intended to go there, you somehow have something getting into the brake system. You'd better figure that out before installing new cylinders or you're going to be back to where you are now in short time. Also, if you don't know how old the brake hoses are, just install new ones. They're about $15 a piece, so worth the money as opposed to having brake problems in the near future.

[old Chevy guy]

How did that baby poop get in the brake system? �� seriously though you should look at the rears too and make sure they don't look like that. Also you better try and flush out the lines before new wheel cylinders so that junk doesn't get in the new ones or was it confined to the cylinders? Was there any in the line near the cylinders? Looks like rust and water.

[midniteblues]

Check out the rubber seal under the master cylinders cap it's job is too seal the resivoir,keeps the fluid in and the moisture out.

Water in the brake system will always travel too the lowest spot (calipers or wheel cly).

Even keeping the master cap off for a period of time the fluid will absorb moisture from the atmosphere.

I would do a good fluid flushing along with new wheel clys.

[Grumpy old man]

Now that is a really good reason to change out the complete system front to back lines and all ! 50 year old brake lines pushing that much moisture is a plan for disaster rusting out from the inside , don't waste any time or money bolting anything new into it . Whatever you add will be junk in a short time let alone dangerous .I wouldn't drive it until it's replaced completely .

[7tee]

Update: 1 yr ago, I installed a new m/c and booster, new rear wheel cylinders and new front and rear shoes. 6-8 months ago new rear brake rubber hose and 2 front brake rubber hoses replaced and was good to go until recently when it started pulling to the right and then shortly after that it started locking and sliding the right front. Today I flushed the system and got clear fluid all around then I installed the new front wheel cylinders and new front drums. Then I adjusted the front shoes until I only got about 1-11/2 rotations with the wheels and tires mounted. Bled the system good and went for a ride and it still wanted to slide the right front. It doesn't pull to the right anymore. When you let off of the brakes the slide and lock up stops...

After returning I jacked the front up and rechecked the wheel/tire rotation, still 1-11/2 rotations. Needless to say I'm pretty frustrated at this point...Ed

[BILT4ME]

What fluid did you use? it should ONLY be DOT3, NOT DOT5.

Did you bleed the brakes through the wheels cylinders until you had clear, clean fluid on all 4 wheels? Always start at the right rear, then left rear, then right front, left front.

When you adjust the drums, you should adjust them out until they are tight, then back them off an even number of clicks. I do 8 clicks on my old Studebaker.

Also, you need to clean the inside of the drum and BOTH brake shoes with Brake Cleaner (preferably the Brakleen in the RED can, not the other stuff....) to remove oil, grease and brake fluid residue. Oil, grease, and brake fluid resifdue can cause the shoe and drum to "stick" like what you have described.

That being said, one of the other posters commented if the LEFT side is working...

If one side is hanging up, you don't REALLY know which is correct. Is the side hanging correct or the other side not working?

You MUST do things in order.

If the problem persists, install NEW front shoes and have the drums turned to remove all contamination. Do NOT touch the face of the shoes OR the inside of the drums with bare fingers OR greasy gloved hands. If the tech turning the drums leaves fingerprints on the surface, make them skim it again at no charge.

You system should have NO leaks. Also install NEW front wheel bearing seals in the event the front wheel bearings keep contaminating the drum.

[Grumpy old man]

Originally Posted by Grumpy old man

Now that is a really good reason to change out the complete system front to back lines and all ! 50 year old brake lines pushing that much moisture is a plan for disaster rusting out from the inside , don't waste any time or money bolting anything new into it . Whatever you add will be junk in a short time let alone dangerous .I wouldn't drive it until it's replaced completely .

Your putting band aids on a broken leg .

[Coley]

Interesting thread.
I have a right rear (drum) brake that locks up on heavy braking. Its not evident under most driving, braking conditions....just shows up under a hard, quick stop with a bit of tire squeal. I have adjusted it once, but it might need another look.
That said, I'm trying to understand how a brake hose deteriorating allows greater braking (Hydraulic) pressure at a given wheel cylinder?...enough so lock it up.
I would think that if a hose is going soft...the hydraulic pressure would be more likely absorbed in the hose 'puffing out' somewhat vs. transmitting that to the brake cylinder. This would mean less direct hydraulic fluid force heading into the wheel cylinder...not more.
Does anyone have any more insight on this?
(also....sorry, not meaning to hijack the thread, maybe just build on it)
All Good
Coley

[old Chevy guy]

Because the hose is restricted it doesn't allow the fluid to return properly hence holding some pressure on that wheel keeping the shoes further out kinda like having one wheels brakes adjusted real tight while all the others are backed way off. I've had that happen with a front wheel with disks and the brake stayed hung up and made the van pull and even locked the wheel and wouldn't roll at all one time.