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Matco Caliper Install Concerns

rapid_ascent

Well Known Member
After replacing my caliper o-rings I moved onto the next step of mounting the wheels and brakes onto the main gear legs. I installed U-810 onto the wheels and then the wheels onto the gear legs. Then I installed the calipers onto the wheel / gear leg assemblies. Earlier I had fitted the calipers to the mounting plate and everything seemed fine. When I went to install the calipers this time it was much more difficult to get the caliper slide pins to slide into the mounting plate guides. Eventually I got it all together, but I'm concerned that I may have a problem later. One brake was dragging a little bit. It didn't seem like the caliper was sliding freely on the guide pins. One side seems worse than the other.

Is this something I should be worried about or will it all take care of itself later once the brakes have fluid? I'd rather fix the problem now than wait until I fill the system with brake fluid.
 
U-810 does not mount to the wheel. Go back and study DWG C-2, SECT A-A. Note R1.

If installed properly, the caliper should rattle on the disc before it is filled with fluid.

The calipers must slide freely on the guide pins in order to work.
 
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Ok, I said that wrong. U-810 is mounted to the flange on the axle and the brake mounting plate. I believe this is assembled correctly. I've attached a pic of before I installed the wheel onto the axle and another before the calipers were installed.

From what I can tell there isn't any way to make any adjustments to how the caliper slides into the mounting plate. So I'm not sure what could be wrong here but something seems not quite right.
 

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The caliper goes on first. Then the wheel with the bearings installed and the disc attached.... Then you bolt on the pressure plate that has the other pad riveted to it.

If the disc scrapes on the U-810, you will need to add washers per drawing.
 
Well I spoke with Matco this morning. They suggested that the proper sequence is to install the caliper onto the mounting plate and confirm that it slide freely before installing the wheel. So I guess the wheels are coming off again. I thought my sequence was ok since previously the calipers did move freely. I may need to make some adjustments. Glad I didn't finish off the axle cotter pin and just installed it temporarily.
 
It appears Matco slider pins might be spaced a bit wider than Cleveland calipers (pictured), so maybe a bit of grinding (hatched area pictured) might be required to clear the wheel pant brackets?
Sorry, my pictures seem to always turn out upside down...
 

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In my case the resistance I have starts way before getting near the wheel pants bracket. Something is definitely different than when I initially put them together. I may have flipped the brake mounting bracket. According to Matco the caliper is shipped from the factory with guide bushing toward the caliper. The bushing is the side without the groove. The groove is actually 2 nuts that are installed on the other side. According to Matco it should work either way. I may flip it around and see if that resolves my problem. It appears at the factory they check that the caliper slides with a specific brake mounting plate. I'm almost 100% sure that I didn't swap the mounting plates between the calipers though.
 
One other thing I just thought of.
Can the brake mounting bracket be bolted to the spindle backwards ( I seem to remember the Cleveland bracket was tapered a bit where it slides on to the spindle)? If that's the case, I see where torqueing down the mounting bolts could distort the bracket.

oops, I see you are going to check that out anyways.
 
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At the risk of throwing a wrench into this thread, if I was to do it over, I'd use the Matco high energy, thicker disc option from initial installation and replace the stock o-rings with higher quality high temperature rings. I had a lot of problems with my brakes - more than any other part of the plane. These were the changes that I made to get my braking system to the reliability that the system demands.

These weren't all that difficult to install after the fact, but it would have been worth doing earlier since most of my brake issues came on a long cross continent trip.

Just to tie this to the original question, the caliper mounts to the inboard side of the flange for the HE option and the outboard side for the standard option.
 
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