The Stovebolt Site Forums The Shop Area Driveline Truck pulls right when braking

Just for fun, my truck started pulling hard to the right when I brake. One day last week it pulled left. Now it pulls right again. The master cylinder was changed last year and I bled the brake lines at that time. I'm looking for your suggestions on what might be causing my issue so I can try to tackle it this weekend. (No sign of leaking brake fluid of a broken line.)

Change the flex lines from the frame to the front wheels. They fail from the inside out (collapse), and restrict the fluid flow to the wheel cylinders.
Jerry

Something loose in front end? Axle moving around or something odd like that?

Could be a small slave leak, soaking the shoes without reaching the outside of the drums yet. A sure sign would be a slightly lower master level.

I would start with a visual on all four corners and master fluid level. Check lines, look at backing plates, etc. Look for small puddles under the vehicle. Eyeball the tires while you're at it. Look for separating tires, low air, etc. Eyeball your suspension while you're at it. If everything looks good, adjust your brakes and go for a test drive. If it still pulls, break out the jack and jack stands and start pulling drums. Start with the front axle as that is the usual area. Issues with the rear brakes can cause pulling, so pull those drums next. Keep looking until you find the issue, then repair it.

Most of the time it is caused by fluid or grease getting on the linings. Like Smith says, it may not be enough to leak out on the wheel or backing plate.
Pull the front drums off & see what you got. File or sand a bevel on the edge of the linings. The reliners used to do this on new linings all the time but they don't put much attention to drum brakes anymore. The sharp edge can cause inconsistant braking.
George

Thank you all for the suggestions.

Oddly enough my 49 3100 started pulling left a couple days ago. Now I have some good starting points to work with! Thanks X2

Any thoughts on Dot 5 fluid? That's what I used years ago when I rebuilt the entire system on my 49 3100.

I have had DOT-5 Silicone brake fluid in my 1954 3106 Suburban for about 20 years.
In new stainless steel brake lines.
No problems.

One you go to DOT-5 you cannot easily changed to a lower DOT-number brake fluid.

I do not think that I will use it in the 1954 3104 that I am restoring.

Good stuff. I was thinking how good it was a couple of days ago. I was topping up the master cyl and I spilled some on the floor. It didn't mess up the paint like DOT 3 would.