mr928 Posted April 4, 2012 Report Share Posted April 4, 2012 So I just replaced all the wheel cylinders and brake lines but for some strange reason I cannot get all the air out. I'm assuming it's air as the first pedal always goes to the floor but with 2 strokes the pedal is nice and hard and stays that way if I hold pressure on it. I've tried vacuum bleeding as well and no change. I've looked for any possible leaks and see nothing. When I manually bleed each wheel I do not get any air bubbles. What am I missing? BTW I used Centrix wheel cylinders which ran me $70 for all 4. Quote Link to comment
mrbigtanker Posted April 4, 2012 Report Share Posted April 4, 2012 First off did you re adjust all your brake pads.Second is it leaking in the drum and you cant see it.Third try it again,start at the back right tire of course.you will get it. Quote Link to comment
datzenmike Posted April 4, 2012 Report Share Posted April 4, 2012 Yes, four wheel drums need a lot of fluid to move them if the shoes are not adjusted. Lift one wheel and adjust it while spinning by hand. Once too tight to turn by hand pump brakes to center the shoes and adjust more if it needs it. Do all four wheels. Quote Link to comment
mklotz70 Posted April 4, 2012 Report Share Posted April 4, 2012 Yep....what Mike said. If you get a hard pedal, you have NO air.....if it stays that way, you have NO leaks. It's purely shoe adjustment. If you have not had your drums turned, it's okay to get a bit of scrub as the wheel rotates. You may hear spots that scuff during rotation, but it should not stop the wheel from turning. Quote Link to comment
mr928 Posted April 4, 2012 Author Report Share Posted April 4, 2012 Thanks for all the tips. I will give them a shot today and let you know. Quote Link to comment
Rambler73 Posted April 5, 2012 Report Share Posted April 5, 2012 Thanks for all the tips. I will give them a shot today and let you know. How did these tips work? I have to work on mine this weekend. Mine r kinda weak and pull to the right. Quote Link to comment
DanielC Posted April 5, 2012 Report Share Posted April 5, 2012 If the brakes pull to one side, you should remove the brake drums, and look at the shoes for grease or oil contamination. If they are not contaminated, and you have a fair amount of lining left on the shoes, put the drums back on. Adjust the brakes, then bleed the system if needed. You should adjust the brakes in a 521 every 3,000 miles. You may need to adjust them more often if you have not adjusted them for a while, until the shoes match the drum closer again. This will need to be done also when you put new shoes in the brakes, or new shoes, and drums. When the brake shoes are in good adjustment, and fitting the drums good, the whole surface of the shoe contacts the brake drum. As the shoes wear, they wear unevenly more and more, and the brake pedal gets softer, as it has to travel more to push the brake shoe into the drum. If it has not been done in a while, you should also repack the front wheel bearings. Quote Link to comment
mr928 Posted April 9, 2012 Author Report Share Posted April 9, 2012 Ok I finally had some time to work on my 521 and it appears that the problem was that the shoes were just too far away. As soon as I adjusted them I had a normal pedal. I guess I'm learning more about drum brakes all the time. Thanks for all the help. Quote Link to comment
konig209 Posted April 9, 2012 Report Share Posted April 9, 2012 Im doing brakes right now too my brake master is no bueno is there an alternate i can use besides stock?its 34.99 here but is there something a lil beter for everything else stock? Quote Link to comment
datzenmike Posted April 9, 2012 Report Share Posted April 9, 2012 $35 is a deal for a master. Were you looking for a larger one? Because larger means you will move more fluid but because the law of "you can't get something for nothing" kicks in you will have to press much harder on the peddle to do so. You could try fitting a vacuum brake booster from a later 620. The master stays the same, but engine vacuum is used to increase the push on it, effectively reducing your peddle effort. Quote Link to comment
konig209 Posted April 9, 2012 Report Share Posted April 9, 2012 Well if stock is good i dont mind stock...its 34.99 at orileys here in town for a new not rebuilt one with lifetime warrenty. Ive never driven the truck yet just trying to get it on the road wanted to bleed the brakes and nothing happened so i took it apart and there is no pressure or fluids getting inside the master Quote Link to comment
konig209 Posted April 9, 2012 Report Share Posted April 9, 2012 Sorry for taking over but this is deff not good right Quote Link to comment
wayno Posted April 10, 2012 Report Share Posted April 10, 2012 If you have the stock drum brakes all around, just buy the stock one, when you start messing around changing things, it can get frustrating. Quote Link to comment
datzenmike Posted April 10, 2012 Report Share Posted April 10, 2012 Sorry for taking over but this is deff not good right The piston my be seized up inside the master. Quote Link to comment
konig209 Posted April 10, 2012 Report Share Posted April 10, 2012 Wait that part inside is supposed to move? Quote Link to comment
datzenmike Posted April 10, 2012 Report Share Posted April 10, 2012 Well hard to say from a picture but there is a piston up inside with a very stiff spring behind it. The push rod (with the dust boot) pushes it in and moves the fluid and the spring inside returns it. Quote Link to comment
konig209 Posted April 10, 2012 Report Share Posted April 10, 2012 Shit hahaha that thing dont even move Quote Link to comment
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