The Stovebolt Site Forums The Parking Lot '60-'66 Trucks drum brakes pull to left

We have a 66 c10 with stock drum brakes. I have replaced the front shoes and one wheel cylinder on the front right. The problem is the truck pulls to the left even after repeated bleeding, and repeated adjustments. i cant't find anything wrong but this is driving me nuts. The pedal is high and solid. Any help will be appreciated, thanks.

No indication that there is any grease/oil on the shoes.

No other issues with the steering?

The alignment bolts for the upper 'A' arms are tight. I had the alignment bolts come loose on a Volvo. The only time there was a noticeable problem was when I used the brakes.

Larry

Thanks for looking. There is not any oil or grease on the shoes or drum. The A arm bolts are tight. The truck stopped good and straight before, but had a seeping wheel cylinder, so i changed the wheel cylinder,wheel bearings and frt shoes and havent been able to get it stop straight since. Is it possible to have the primary and secondary shoes on backwards on one wheel and not have the same stopping power as the other wheel?

One thing you haven't considered is the condition of the flex lines from the frame to the hubs. Flex hoses have a habit of deteriorating from the indside, with no evidence of problems from the outside of the hose. A restricted line on the left, for instance, will allow pressure to go to the right wheel cylinder first, allowing a pull to the right. In some cases, the pressure will get trapped downstream of the hose, giving a pull to the opposite direction when the brake pedal is released and pressure stays in the wheel cylinder on the other side. One quick way to check for a restricted line is to have someone step on the brake, then release it, and check for a wheel that takes a while to turn freely. To distinguish between a bad hose and a sticky wheel cylinder, open the bleeder screw quickly after the brake is released. If you get a squirt of fluid, the hose is the problem.

Edit: Yes, getting primary and secondary shoes reversed on one wheel will cause the brakes to pull toward the side with the brakes assembled properly.
Jerry

I had this problem one time and somehow while working on the truck I had dented one the brake line that ran to the right side. If you can't find anything wrong I would change out the other wheel cylinder. Maybe the reproductions are made a little diffent and the preasure just wont match up. it seams to me that if there was enough of a difference in the bore size inside the cylinder then they would never move the same amount at the same time. I could be wrong and Im sure if I am someone will point it out

A common mistake with brakes pulling to one side is the assumption that the problem is on that side. It is most likely on the opposite side. That side is working fine.

You may want to put a bevel on the edge of each lining. Sometimes the sharp edge digs into the drum. Especially when the drums are a little diff. dia. They used to cam grind new shoes when they relined them but they don't do it anymore.

I had an old Bronco once that always pulled to one side. I did everything I could think of and finally sold it. The guy who bought it took it to a garage and they found the opposite rear wheel seal had gone out and got 90 weight on those shoes. Because that side wasn't working on the rear, it made me think something was wrong on the opposite front.

It is also possible that your new wheel cylinder is a different bore than the old one. It is common for wheel cylinders to have different bores for different applications, yet the outside will look the same and bolt in. I personally will not repair one brake. I will always do both brakes on the axle to make sure they are matched.

lg
no neat sig line

native66, it is actually as 61nate and larry_g say, if one wheel cylinder is of a different bore it will have a different pressure applied to the wheels than the other side. So that is a point to consider.
As well, as stated if there are problems with dents in the lines or hose issues fluid flow can be the problem.
I would start with a change of brake hoses both sides (unless you know the history of the hoses (ie, just changed last year) and replace the other wheel cylinder to make it a matched set.
The other thing I recall on drum brake adjustment is that the shoes on both sides need to be about the same distance away from the drum. One side adjusted close to the drum and the other a bit farther will take some time for the auto adjusters to get aligned. Thus a pull to one side.
Then as mearl says, check the back brakes, they may be causing the problems.

The new wheel cylinder will be a different size than the old one , granted it will likely be minute . Also , the possibility that the old cylinders had been honed in the past makes this even more likely .I would replace the other side wheel cylinder and see if that makes a difference .

If its grabbing the steering wheel its probably the fronts, I always replace hydraulic parts in pairs, brake hoses, wheel cylinders etc. to make sure of equality in operation, just my opinion..