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Hello,

I've started having brake fade where it takes many pumps (12 or so) of the handle to get any pressure.

I have marc brakes, with a Matco master cylinder installed 2 years ago. I have about 1020 hrs on the plane.

 

The fade would occur after taxiing on the grass home strip. I rebuilt the master cylinder, and bled the system. Tested Ok in the hanger. The pins are clean and disks are floating. Pad thickness is good. Still got loss of braking on taxi.

 

I finally manually retracted the pistons into the caliper by pulling on each disk. I found that retracting the left piston caused the need for pumping. I think the wheel vibration while taxiing on grass is making the piston retract.

 

Matco brakes are on order.

 

I'm having the opposite problem of what others have reported about Matcos. Must be brake month.

 

 

 

 

 

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 Hi Bill,

 

Marc brakes were famous for the pumping and fading. That's one reason I got FD set up with Matco. I have always thought Marc brakes were trash. The Matco master cylinder swap with the Marc's helped some. I ended up slightly enlarging the disc holes to make the disc float better. It helped, but the Marc's still fade when braking as heat builds. Not terrible if all you want to do is slow a tad, but one day I almost hit a fence in Washington because they got hot and braking started to disappear. When I got home Matco's for CT's were born. Your caliper pistons and or piston "O" ring may be getting worn or moisture.  Grass strips have a lot of moisture and are hard on brake calipers in the long run which may have corroded the inside barrel where the piston rides. This would warrant a caliper pull and removal of the piston. Scotchbrite the piston barrel and new "O" ring.

 

 

The reason you had to pump when you pushed the piston back in was to push the piston back out to exert force on the pads to the disc,

 

You'll be a lot happier with the Matco's over the Marcs.

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Data point:

About 9 years and 430+ hours with Marc brakes on my Sky Arrow. Still original pads and have never faded.

Did have one piston sticking in it's bore, fixed by disassembling and cleaning/polishing. Keeping the rotor pins free of corrosion and possibly lubed helps as well.

Not denying that Matco's might not be an order of magnitude better, but just saying that Marc's are not all that terrible, and that the problems you're describing probably indicate a real issue, not an inherent weakness.

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Hi Roger,

Pushing the caliper piston manually was a debugging technique. I expected to pump after that. The surprise was that just taxiing was causing that problem. Thought maybe disk was seized and wobbling, but  not the case. This has been slowly getting worse (that's why I replaced the master.)

Time has just come to get over the problem.  I've seen others are much happier with Matco.  I also didn't know a source of rebuild parts for Marc calipers.

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I got 10 years out of my Marc brakes and they still work pretty good.  I'm now ready for Matco and an upgrade to Monster treads (if they will fit in my wheel pants) and alignment/balance.  Would be nice if  my gear were more 'quiet'.

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I gave up early on with the Marc brakes. Had to change the P in GUMP to pump if I wanted to have useable brakes after touch down.

 

Well worth the cost.

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My Marcs sucked and just got worse.  Matco seem better in all ways, including cheaper and available parts.  Isn't it true that, with Matcos, you also get alignment adjustability?

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I guess I'm in the minority. The Marc brakes on my CTLS are still working great at 600 hours. All of you guys who are taking them off feel free to send them to me, and I'll put them to good use as spare parts.

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I have seen two 2008s I knew well with Matcos on them. As far as I know neither was converted. Doc Ron's is one of them.

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I have 730 hours on my Marc brakes with no issues. I replaced the pads and pins at 600 hours only because I was flying to Page. The pads were 2mm and can be worn down to 1mm.

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Spring removal was another attempt to make them so you did not have to pump them so much.

 

I first removed the springs, then I opened up the disc holes a tad. All seemed well until I really needed them and when they got a little hot they faded so bad I almost tagged a fence. When I got home I took them off and put Matco's on. That was mid 2007.

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This may have come up before, but where are those springs you're referring to?

 

When I had my piston out to clean/polish the bore, I don't recall seeing anything like that.

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The springs are on the caliper guide pins. They help push the pads away from the disc. They pushed them so far apart you had to pump the brakes to build up pressure again to get past the spring tension pushing them apart.  They did too good of a job. Then the disc like to get bound up on their guide pins. What a zoo. :fainting-1344: 

 

Then the next fix band-aid fix was a Matco master cylinder. It has almost twice the pressure and a lot more fluid volume. The other issue is the wheels are stamped out of too thin an aluminum. If you add too much pressure or allow them to have too little pressure the wheels flex and change size enough to cause the disc to bind.

 

The Italians here are definitely living in the past or their engineers for this company need more education. 

 

For me the bottom line for Italian made Marc brakes was the shooting range. :giggle-3307: 

 

 

​I guess you have figured out a don't particularly like these brakes.  :laughter-3293: 

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Roger,

Could you please tell me the size hole you drilled in the new shafts?  My drill/tap table says 8.8mm for clearance, 8.4m for tight clearance for the M8 through bolt. I don't have a good machine shop, but a friend does. I want to buy the right (good) bits first.

 

Oh, I'm trying to avoid "tagging a fence" at the Arlington fly-in.

 

Thanks,

Bill Mc.

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Hi Bill,

 

It's been a while and I truly can't remember, but  if you get it too tight you'll never get it in. Start small and if necessary ream it out a tad if it doesn't fit. I do know it isn't that crucial. When you tighten that bolt down it will not move. Hole size may not be as hard to do as getting a perfect alignment.  Everyone here wants it perfect, but that doesn't always happen and it never seems to make a big difference.

 

For the SW:

Make sure the new spindle is perpendicular to the ground. If it isn't any adjustment you make from then on out will be a compound angle and not quite straight. Put a square type level on the ground and put the face of the new spindle up against the straight edge. This will get you square to the ground. Make the plane reasonably level as it would be sitting on the ground with a wheel on so when you set and check this angle the wheel is not way up in the air out of it's normal position.

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