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BJ8 caliper rebuild???????

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fordtrucks4ever

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Has someone devised a reliable way to install the piston dust covers on calipers? These are not much different than the first 30 years of Ford and some AMC/Jeep calipers. But tend to be a much bigger pita. I could be on the road today shaking some more bugs out of my car, if these calipers would be more cooperative....Is this going to become the normal for keeping a British car roadworthy? Or is that an oxymoron?
 
fordtrucks4ever said:
Has someone devised a reliable way to install the piston dust covers on calipers? These are not much different than the first 30 years of Ford and some AMC/Jeep calipers. But tend to be a much bigger pita. I could be on the road today shaking some more bugs out of my car, if these calipers would be more cooperative....Is this going to become the normal for keeping a British car roadworthy? Or is that an oxymoron?
Click to expand...


Patience and more patience and some tea .....
 
Hi Terry:
I found splitting the caliper, using new O rings and SS pistons made it easy for me .
 
FWIW all I use are original stock covers , not that hard to find on Ebay or internet stores, they must be quality made or will give you headaches

Carroll Phillips
Top Down Restorations
 
Follow up on rebuilding the calipers. Very simple after trying several different ways. Without wasting time in what didnt work as well, this is what I did. One way that did work was using a plastic sleeve that just slides over piston. It stretches the dust seal open making it easy to fit the little lip into the groove in housing. I made the sleeve out of a piece of 2" pvc. I chucked it up in the lathe and machine both inner and outer diameter to fit. Very thin wall and just large enough to slide over piston. It is only about 1/2" wide. Without splitting the caliper halves, since its written in bold print everywhere not to ever do this, use your finger to push the lip into the groove. Then drop piston in and its done. It worked great on two of the dust covers. The third one seemed a little smaller and needed to be stretched to stay fitted in the groove. This one I gave up on the sleeve. Then it actually got easy. I stretched the dust cover over piston and let the lower edge with lip hang down below piston. Dropped it down into caliper and carefully worked the piston down in the bore. I think this is the way they are made to be installed. The piston pushes the lip into the groove as it slides down into the bore. What is an absolute necessity must have to do is lubricate the lip on dust cover. I got my fingers a little slippery with Vaseline and wiped the lip. Just enough to make it shiny. Not all wet and sloppy looking. Just wipe on wipe off. This made the lip slide in groove so much easier without much effort and consistent. You also need to wipe the square cut oring with brake fluid so the piston will slide down in to bore without much resistance.

What nobody mentioned is the sqaure cut orings only fit one way. There is a smaller diameter edge that is almost indistinguishable. It faces down in the bore. When oring is installed in the bore correctly you can feel it taper smaller when running finger over it. Thats my story and I am sticking with it.
 
Au contraire fordtrucksforever, the square section o-ring fits either way when it is new. There is no difference between the edges when it is new. However, after many years of use, the o-ring becomes distorted because that is what pulls the piston back away from the rotor after the line pressure is reduced (when you take your foot off the brake). That is why the o-ring is square instead of round in the first place.
Secondly, Keoke is right about splitting the caliper to make the rebuild much easier now that we can get the special o-rings that go inside the calipers.
 
These are new orings I just removed from a rebuild kit. At it also mentions this in the factory manual.
 
I had the same problem with my rebuild. After a wasted Saturday and a couple torn boots and one installed I ordered another set. The first set was poorly made, slightly too thick, and had some excess flash on the rubber. The second set, while still somewhat of a pain to install, went on much quicker and a much more moderate level of bad words. This was on my TR250, but same calipers as a BJ8.
 
I've split the P16 type calipers in half every time I've rebuilt them for other makes and never had a problem with leaks afterward. Splitting them makes it much easier t clean out the grooves for the piston seal and the dust cover. When doing this I use a small cutoff wheel for the dust seal groove, run it around a couple times and all the old dirt, rust and stuck rubber bits are gone. Small circular square edge soft stone for the piston seal groove to clean up any rust spots and dirt. Can't really hurt the caliper with these, they're not hard enough to cut into the metal unless you work at it.
 
China cup::

---------------------------------China cup !!!,Whats wrong with fine English China???----:highly_amused::
 
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