Brake problem, your expertise is welcome

The truck is off topic but the subject is not. I have spent two years trying everything I can to get my brakes to act right and I am at a loss. I have been replacing Ford brakes for about 45 years, I'm not a novice.
The truck is a 1960 1/2 ton Ford with Stock brakes, nothing unusual except that when I apply the brakes, the truck violently turns right, jerking the steering wheel out of my hands.

I have replaced the tires with new ones, several times.

I have tried different Ford rims, several times.
I have tried different brake drums.
The bearings and races have been cleaned, inspected, packed with new grease and swapped to the other side of the truck.

Several sets of new brake shoes, Bendix brand
Replaced the wheel cylinders, several times. The micrometer shows that the pistons and bores of the cylinders are Ok and matching, no burrs anywhere and the pistons move freely.
I find no fault with the backing plates and have polished and lubricated the pads that the shoes move on.

Brake hoses are new and thoroughly inspected, I can see daylight thru them and no irregularities inside. They are mounted to the frame the way Ford intended.

The brake lines have been taken off the truck and inspected, no crimps, no pinched places, free flow .
The master cylinder could not cause this but it has been replaced twice anyway.
The camber has been checked, o degrees, which is correct, no bent spindle or axle as best I can determine.
Caster is 3 degrees on both sides, correct by the book.
The spring packs have been disassembled, cleaned, inspected deburred and properly reassembled with new rubber in the shackles
All the bolts are tight on the axle, springs, shackles, etc.
Toe-in has been checked with every set of new tires, kingpins and bushings are new, no play. Tie-rod is tight and straight.


I have checked the wheel base on each side of the truck and inspected everything on the rear axle just in case and friends say the truck tracks straight while driving.
Thats all I can remember checking right now, I sure would like advice.

 

I can't add anything but I am going to watch this to see if you have an outcome. You have tried everything and then some I would have. Does it happen every time at all speeds or is it fine some days then then does it all of the sudden?

 

Drive down the edge of pavement left wheel on pavement right off and stop. If it still turns right the left wheel isn't not brakeing. if it turns left look ant right side. Are the pirmary and secondary shoes in the right place?

 

I had a similar problem with air brakes on a trailer . One brake can was receiving air quicker than the other three. My problem was with air, yours are brake fluid operated. If my memory is correct your truck is a non booster application. I was thinking that you right front brake was getting fluid before the others . But the left front has less line for fluid travel.

Are your front drums the same equal thickness. Even though you replaced the wheel cylinders are the pistons true to the bore and lubed properly? I'm sure you adjusted the brakes evenly. I would also check the thickness on each lining . One may be off a couple of thousands off .

Hope this help you out .

 

http://www.piratejack.net/index.php?option=com_content&view=article&id=11:typical-brake-system-configurations&catid=12:tech-support&Itemid=18 Brake set ups Bill aka Tnomoldw

 

The brake shoes need to be arced to the drum ,only a brake shop can do that. Bill aka Tnomoldw

 

Sounds like you've ran the gauntlet on this one.
I would back up and swap sides again to eliminate that or narrow it down. Just incase you missed something. If the problem stays and you are certain the primary shoes are correct, I'd look again at fluid and pressure delivery and variances.

You would think that if it is so violent has to jurk the wheel out of your hand the problem would be obvious.

 

If you get out in the middle of a big empty parking lot and make a bit of a run up to say 30 mph and lock up the brakes what do the skid marks look like?

I'm thinking that the problem is the left side not working right rather than the right side hooking up too fast.
You checked the lines and hoses but did you check any brass fittings that may be in the line? I'm wondering if there is a T or other fitting that has an orifice with a reduced size on it that is limiting the flow of fluid to that side or if one line on one side has been replaced with a larger diameter line. You have already done and checked just about everything that those of us who have done a lot of brakes in the past would have done so it has to be something so simple it is being overlooked.

In the past I have ended up fixing brake issues that someone did their own brakes on where they put the primary shoes on one side of the car and the secondary shoes on the other causing it to pull. I've also redone a lot of brakes where they did one side and mirrored went around to the other side and reversed the shoes so that the primary was in the rear and the secondary was in the front. Remember the shoe with the least amount of lining goes to the front and the one with the most lining always goes on the rear. But as this truck has been through several brake jobs I'm a lot more inclined to bet on a restriction or size difference in the line.

 

That might cause a spongy brake as the shoes flex a bit until the lining wears in but won't cause it to pull like that.

 

I had a similar problem on my 36 ( had a 60 something straicht axle under it at the time )it turned out to be the spring kit that holds/retracts the shoes for some reason one side did not have the same tension the outher did I could not tell this while I was reassembling them but the new spring kit fixed it up.

 

very remote possibility here, but on my brothers 59 Galaxie, the rears weren't working. He tried everything, and finally pulled the rubber line at the rear axle, and found a chunk of rust preventing fluid flow, although it sounds like that has been eliminated already.

 

How are the shoes arced to the drums? Even close to the same shape? Many miles on them?

Has the caster been checked? If you have too little caster, maybe the spindles want to turn too easily, and during braking is a good opportunity. Does the truck steer easily when you don't apply the brakes?

You say the backing plates are good, but? Can you verify they are not twisted or bent somehow? Make sure the shoe pad points are all on the same plane.

Buy a new hardware/spring kit. They are cheap, and will help you eliminate one more possible culprit.

When you adjust the shoes, are you also moving the mounting pivot stud at the top of the plate? It is used to move the shoes up and down depending on the diameter of the drums.

Has your steering box been centered correctly? Not just centering the wheels, but centering the box first, then move the wheels to center by adjusting the drag link.

 

Put a 45 degree "ramp" on the leading edge of the material on the brake shoes . Dosn't affect braking performance but it will take the "whack" out of it .



.

 

did you replace the rubber lines when they get old sittin along time they can swell on the inside and even let a little fluid through under pressure but not enough if you take them off you shoul tell by how well they drain with just gravity

 

I can attest to the fact his truck track's true and sits good all the way around.
I think manyolcars need to make a brake related trophies for who ever solves it!

 

Sounds like you've covered everything well, BUT, you haven't said when did this start? Has it always been? Did you make mods to the truck, then it happened? Did you do a brake job, then it happened? More info on what might be the cause will give us more to go on.
As you know, hydraulics are fairy simple, either the right front is doing all the work, or some thing else is not doing its job. It really sounds to me that you've got something stuck in a hard line, take one at a time off each wheel, you'll need a friend, stab the brake pedal, see which one the fluid comes out of slowest. You've covered it all, I'm curious.

 

Brake related trophy ??

Fuid or pressure delivery problem on left side.

Or

Suspension bushing issue that moves under brake toque and throws alignment off on right side

 

Several other things come to mind.
1 Are the shoes installed the correct way ie short lining to the front?
2 Do you have miss matched lining ,that is shoes on one side installed at a different time or source?
3 As said how do the shoes fit the drums on both sides?
4 I may have missed it new hoses and good flow to both sides when bleeding?
5 Front suspension issues tie rod ends ,kingpins,spring bushings etc.

 

things to check #1 there are primary and secondary shoes
brake shoes are shorter on the primary side and they always go on the front and the secondary shoes go towards the rear.
#2 make sure wheel cylinder is not seized up on opposite side
#3 pull the brake shoes off and take a look at where the brake shoe rides on little pads on the backing plates. I've had to weld up grooves and grind them back to standard.
#4 check for broken and missing hardware and springs that have lost there tension. Drop a brake spring on the floor and if it sounds like a ringing noise replace it, brake springs
should only have a dull thunk sound when dropped.
Remember, these are self energizing brakes, the primary shoe comes in contact with the drum first and twists the secondary shoe in the drum.
Go back to basics and you will find your problem.

 

Probably is something not related to the brakes at all, like drag link or tie rod, or leaf springs or leaf spring bushings or shocks. Had a parrallel leaf Ford once that got real dodgy when the brakes were applied and it turned out to be a bad leaf spring (broken leaves). An aquaintence had a '58 Ford with a camper that got all squirrely in the corners, and having had the problem with the other ford I replaced his springs and added a pan hard bar and air shocks etc. Then by some freak of the imagination while I was scratching my head he bumped into the side of the truck and I saw that the centers of the wheels were flexing. Replaced the wheels and it cured the problem.

Anyway I said all that to say that it is probably not the brakes.

 

I too am thinking if it can jerk the steering wheel then one front brake is inactive.

If both pistons in each of the wheel cylinders are indeed confirmed free moving seems like real life wheel cylinder pressure test should show something.
http://www.amazon.com/OTC-7488A-Brake-Pressure-Test/dp/B00063W7L6
seems like it should be possible to rig something up for way less. I'm thinking 2 bleeder screws, 2 high pressure gages, some intermediate hardware.
With the front in the air and the wheels off, a long pipe welded to an old wheel center could be used to test both sides for major resistance when the brakes are applied medium hard.

 

swap side of the entire brake. drum,backingplate,
cyl,shoes,springs.does it pull to the other side?
yes! brakes is failing! no, problem is elsewere
I think left brake is not working. Or right wheel
get out of place while braking, loose stearing arm,
sloppy stearing joint, slopy spindelbolt, etc etc

is it self adjusting brakes? is the adjusters on the
right side ?one side is left tread one is right tread
and do the adjusters move frealy, got all the
toths intact?

 

This problem comes here often with new shoes.
The way it was done without a arching machine.
Cammfer the new lining back about 1/2, angle and depth 1/8 on ends.
At least near "first rivet".
If you bring the shoes out even 3-9 oclock 1/8 less then drum.
Most likly they will hit on top thats what the cammmfer is for,
do both end.
The pistons must be all the way in.
The high lining stops the piston from going back in.
The angle can be done with file or bench grinder thats what i use.

 

I would say weak return springs on one side.

 

My friend car had a problem like this, car would track straight and drive nice but hit the brakes and it would swerve violently. We figured out the rear axle was loose from the springs, going forward no problem hit the brakes one side would shift about 1 inch and cause it to swerve

 

What about the wheel cylinder on one side letting pressure off fast and the other slowly? Causing the M/C to play catch up when brakes are reapplied. Maybe a residual valve is needed or two. Also is this a single pot M/C?

 

I had this happen on the rear of a car (drum). It turned out to be cracked linings. I know you've changed shoes, perhaps change brands?? Or try a relining company (Auto Clutch and All Brake 'round these parts).

Cosmo

 

Thank you for the responses guys! This is a lot of great information.



Running thru your posts in order, post number 2, this is all factory swedged parts
Post 3 it happens all the time. I can start the engine and pull forward 3 feet and if there are no hands on the steering wheel, it will spin the steering wheel so hard you expect the wheel to break off the column when it hits the stops..
Post 4 I agree that it seems like the left side is not working but the drum and shoes show wear and when I pull the left drum off and press the brake pedal, I see the shoes expanding. Of course the primary and secondary shoes are on right
Post 5 The brake line goes from the master to the left frame rail where it Ts to the left side then the line goes all the way around to the right side. The left side line is about 5 or 6" long. No way the right side gets fluid first and anyway the Law of Hydraulics says that doesnt matter. Equal thickness drums? doesnt matter. I have swapped the drums and if it was a drum problem, the trouble would have moved to the other side when the drums were swapped. See the first post for piston and bore measurements.
Post 6 and 7 The arc of the shoes is a perfect match to the drums
Post 8 I agree, its so bad the problem should be obvious
Post 9 I agree, it seems to be the left not working, except for wear on the shoes and drums. I did check the brass T when I took the 5 or 6" line off

and as you say, its always something so simple it is being overlooked.I agree with that! a larger diameter line? Nope, all factory stuff
Post 10, yeah
post 11 I wish it was that easy!
Post 12 ?
Post 13 I edited post one to include the caster I had forgotten. I dont know how to be Positive the backing plates are not bent but I have looked closely at gaps and the wear on the rub pads. The shoes might show uneven wear with a bent plate. They are wearing evenly. The spring kits were new but who knows with chinese junk. All the springs feel strong. The anchor bolts are factory solid on the backing plates, no movement. You have lots of good ideas.
Post 14 the shoes have the ramp. These are top quality Bendix shoes
Post 15 new rubber, again, might be chinese. We are going to wrap fingers around the left side hose and press the pedal to see if the hose 'ballons'.

Post 17 You guys dont miss a thing, do you? It started about 2 years ago after I replaced the kingpins and bushings. I have been doing that to old Ford axles since 1967. I'm pretty sure I did it right.
Post 18 I agree. I think the left side is not doing its job. I have thought about the suspension Thats why I mentioned new rubber in the shackles and all bolts tight. I got a friend to stand by the front wheel and watch for movement while braking. This is a simple axle assembly with only a few parts.

Post 19 repeat
Post 20 all repeats. I do believe when I find it, it will be something simple and basic. Maybe you can see what I missed when you read Post One.
Post 21 Hi porknbeaner!
Post 22 repeat
Post 23 Wouldnt it be nice to have a gauge! maybe I can rig something
Post 24, everything swapped to the other side in post one, no change
Post 25 repeat
Post 26 repeat
Post 27 covered in post one
Post 28 ?
Cosmo, I bought Bendix riveted shoes because I think its the best we can get. . Is there a better quality shoe available?


Again I appreciate every ones help and I will check the things that you all have suggested. I have the brakes down to bare backing plates and do not want to reassemble until I find a suspect.

 

ssbc sells a brake pressure gauge kit for around $50 might be what you need to check the pressure at each wheel or maybe have a friend step on the brake pedal after you have disconeected the hose at the wheel cylinder and see how the fluid flow looks

 

I'm with 59 brook.....I've seen the inside of the flex line crack and actually act like a check....so checking the pressure at each wheel should verify it....or swap flex lines to see if the problem moves?