Brakes fail "on" ??
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xkfeng7
- Posts: 31
- Joined: Mon Aug 13, 2012 3:33 am
- Location: Boston, MA
Re: Brakes fail "on" ??
Update: I finally got a respite from work/travel and put the W11 up on stands.
Front brakes are working fine. Rear's are stuck on. I tried releasing pressure from one bleeder, but no fluid came out! So, I suspect something mechanical.
I'm going to completely redo everything this winter anyway, but thanks for the various bits of useful info posted here on brake parts.
Front brakes are working fine. Rear's are stuck on. I tried releasing pressure from one bleeder, but no fluid came out! So, I suspect something mechanical.
I'm going to completely redo everything this winter anyway, but thanks for the various bits of useful info posted here on brake parts.
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Westfield 129
- Posts: 867
- Joined: Sat Jun 04, 2011 4:20 am
Re: Brakes fail "on" ??
Not too many parts in the rear brake setup, so plan on replacing both rear wheel cylinders. These parts are not really very robust, and are prone to rust and failure every few years, even if you religiously flush the brake fluid. Generally, they will show leakage when you pull away the rubbers. I have had my 11 About 9 years, and have installed two new sets of wheel cylinders. My last set is doing quite well, though. I have switched to Valvoline synthetic brake fluid, and flush it every year.
I use a vacuum bleeder that is compressed air driven. Very fast and very clean way to flush the brake system with fresh fluid.
When you take apart the brakes, note the position of the shoes, and where the gap is. I have often seen the shoes installed backwards, so take a good look at the manual and your rear brakes to make sure that you get them back in correctly. Lack of rear brake authority can be sometimes be traced to improperly installed shoes. I believe, if memory serves (well, it works most of the time) that the gap is on top of the leading shoe.
Fortunately, shoes are inexpensive, and relatively easy to replace. While you are back there, taking things apart, check the linings for fluid soaking, clean the adjusters (don't forget the threads, too), maybe even take off the back plates and remove the rust and re paint them.
If you want special linings (Performance Friction or Porterfield), you can usually find them in your favorite supplier's catalog, or you might have to send them off for relining. I always keep a couple of sets around just in case I want to try something special, and send those off to the specialty supplier for relining.
You might even turn the rear drums, but replacements are very inexpensive as well, so you might replace them as well.
When re assembling, don't forget to put some grease at the contact points between the shoes and the back plates. When you finish, re adjust the brakes BEFORE you connect up the rods and clevis pins.
I use hitch pins in place of cotter or split pins so that I can easily disconnect everything for brake adjustments.
The adjusters are pyramid shaped, so you may have to force the adjuster to the next flat for the best and tightest adjustment. This will improve both the hand brake and rear brake authority, as well as making a more solid pedal, with a more accurate feel.
If you have a 40 year old car that has mostly original parts. you might consider changing EVERYTHING. Master cylinder, both front calipers and the rear drums, shoes, and wheel cylinders. You can do all the work yourself, and the cost for the parts is not crazy. Rebuilding those old master cylinders is not always successful, and those old wheel cylinders and calipers are very pitted inside, making rebuilding impractical. The cost for new calipers is relatively low, so having a new braking system is certainly practical.
To make sure that everything works best, install a set of taper front wheel bearings. This will eliminate any play that the ball bearings have, and will give you a solid, predictable pedal.
I use a vacuum bleeder that is compressed air driven. Very fast and very clean way to flush the brake system with fresh fluid.
When you take apart the brakes, note the position of the shoes, and where the gap is. I have often seen the shoes installed backwards, so take a good look at the manual and your rear brakes to make sure that you get them back in correctly. Lack of rear brake authority can be sometimes be traced to improperly installed shoes. I believe, if memory serves (well, it works most of the time) that the gap is on top of the leading shoe.
Fortunately, shoes are inexpensive, and relatively easy to replace. While you are back there, taking things apart, check the linings for fluid soaking, clean the adjusters (don't forget the threads, too), maybe even take off the back plates and remove the rust and re paint them.
If you want special linings (Performance Friction or Porterfield), you can usually find them in your favorite supplier's catalog, or you might have to send them off for relining. I always keep a couple of sets around just in case I want to try something special, and send those off to the specialty supplier for relining.
You might even turn the rear drums, but replacements are very inexpensive as well, so you might replace them as well.
When re assembling, don't forget to put some grease at the contact points between the shoes and the back plates. When you finish, re adjust the brakes BEFORE you connect up the rods and clevis pins.
I use hitch pins in place of cotter or split pins so that I can easily disconnect everything for brake adjustments.
The adjusters are pyramid shaped, so you may have to force the adjuster to the next flat for the best and tightest adjustment. This will improve both the hand brake and rear brake authority, as well as making a more solid pedal, with a more accurate feel.
If you have a 40 year old car that has mostly original parts. you might consider changing EVERYTHING. Master cylinder, both front calipers and the rear drums, shoes, and wheel cylinders. You can do all the work yourself, and the cost for the parts is not crazy. Rebuilding those old master cylinders is not always successful, and those old wheel cylinders and calipers are very pitted inside, making rebuilding impractical. The cost for new calipers is relatively low, so having a new braking system is certainly practical.
To make sure that everything works best, install a set of taper front wheel bearings. This will eliminate any play that the ball bearings have, and will give you a solid, predictable pedal.