8KCAB Brake Master Cylinder overhaul

[Bradc16]

Sorry about that Bartman, I went through the same process. I did not mention it here because they had already corrected their website. Planeparts Inc. was very good to work with.

 

[Bartman]

Yes, Bob from PlanePartsInc.com was very quick to reply and I spoke with him this morning, he's already sent two new kits for the Gerdes A110-10 cylinders via Priority Mail so I'm happy.

 

[Big Ed]

About to start the same project. So if I
have the Gerdes A-110-10, I should order the correct kit from PP LLC, there is no kit available from AS INC, and the Cleveland 10-54 will not work,correct?

I also have a leaking caliper. Do I need anything other than a new O-ring?

 

[Bradc16]

That is correct if you want a kit. If you don’t want to order it as a kit you could probably get all of the correct o rings from a parts supplier using the part numbers. The lock nut and snap rings can be reused.
Planeparts was very fast to ship so I would recommend just getting their kit.
I have not had to tackle the caliper yet.

 

[Big Ed]

That is correct if you want a kit. If you don’t want to order it as a kit you could probably get all of the correct o rings from a parts supplier using the part numbers. The lock nut and snap rings can be reused.
Planeparts was very fast to ship so I would recommend just getting their kit.
I have not had to tackle the caliper yet.

Thanks, I found the kits on eBay from PP, so I ordered a pair. I ordered caliper o-rings from Spruce. Hopefully I don't need any other caliper parts, as they are crazy expensive.

 

[Bob Turner]

The bores can usually be cleaned up with Scotchbrite. I have (a long time ago, beyond any statutes of limitation) used JB Weld in badly pitted bores.

The one thing that seems difficult to fix is chatter. I do not know the pin tolerance that allows chatter, but I had it on one caliper and wound up replacing both pins and torque plate.

Most Champs use the 30-19 caliper. Parts are identical to the one Robbie Grove produces for the J3.

 

[Big Ed]

The bores can usually be cleaned up with Scotchbrite. I have (a long time ago, beyond any statutes of limitation) used JB Weld in badly pitted bores.

The one thing that seems difficult to fix is chatter. I do not know the pin tolerance that allows chatter, but I had it on one caliper and wound up replacing both pins and torque plate.

Most Champs use the 30-19 caliper. Parts are identical to the one Robbie Grove produces for the J3.

My torque plates have been bent and straightened at some point in their 45 year history. Cleveland replacements are absurdly expensive. Anyone know of a cheaper alternative?

 

[Bob Turner]

The problem is unapproved parts. If Robbie got a PMA you could use his. I can probably check; I owe them a visit.
Still sort of careful about where I hang out indoors.

Grove FAA Certified Parts

 

[Big Ed]

The problem is unapproved parts. If Robbie got a PMA you could use his. I can probably check; I owe them a visit.
Still sort of careful about where I hang out indoors.

Grove FAA Certified Parts

RAPCO and MATCO produce aftermarket discs and shoes ... was wondering if maybe they produced torque plates, et.

 

[Bob Turner]

I believe, but am not sure, that ACA is using Grove wheels and brakes on new aircraft. Problem is, ACA holds the PMA. I think.

 

[Bartman]

About to start the same project. So if I
have the Gerdes A-110-10, I should order the correct kit from PP LLC, there is no kit available from AS INC, and the Cleveland 10-54 will not work,correct?

I also have a leaking caliper. Do I need anything other than a new O-ring?

Bob from PP sent me a kit that is specifically labeled for the Gerdes master cylinder and it included new snap rings and a jamb nut in addition to the o-rings. The service manual covers this rebuild and mentions a teflon seal but I didn't see a seal when I did mine.

Anyone familiar enough to explain where the seal is?

 

[Bradc16]

There was no additional seal in my Gerdes A-110-10s. Could that be in reference to sealing threads on the fittings?

 

[Bartman]

Possibly, I've got a spare at the hangar that looks low time so maybe it's never been rebuilt. I'll bring it home and pull it apart later today, will post photos.

 

[Bradc16]

 

[Bradc16]

This is as I disassembled, the first was after polishing during reassembly.

 

[Joe]

Master cylinder from my 79' 8kcab. Gerdes A110-44, yet another variation. Used a MS28775-012, MS28775-112, and MS88775-111, Same o-rings as the Cleveland 10-54 but did not take the stat-o-seal washer. I didn't check the parking valve for a model number but it took, 2ea MS28778-4, 3 ea MS28775-010 and 2 ea MS28775-007. The parts book called for an -008 instead of the -007.

 

[Joe]

I am changing my 1979 brake hoses while I am at it. My guess is that the hoses at the master cylinders are made from Aeroquip 303-4 bulk hose, and the hoses down at the calipers are made from Aeroquip 601-4 hose. If anyone here has experience with these, can you confirm if I am correct.

 

[Bartman]

Master cylinder from my 79' 8kcab. Gerdes A110-44, yet another variation. Used a MS28775-012, MS28775-112, and MS88775-111, Same o-rings as the Cleveland 10-54 but did not take the stat-o-seal washer. I didn't check the parking valve for a model number but it took, 2ea MS28778-4, 3 ea MS28775-010 and 2 ea MS28775-007. The parts book called for an -008 instead of the -007.

does that cylinder have a Gerdes tag on it? looks more like the Cleveland 10-54

 

[Joe]

does that cylinder have a Gerdes tag on it? looks more like the Cleveland 10-54

If you blow up the picture it is stamped on the cylinder. Gerdes A110-44. it appears to be the same as the Cleveland 10-54 with the exception that mine do not have the Stat-0-Seal washer between the shaft and the piston. But if my memory is correct Bobs Cleveland 10-54 also did not use the Stat-O-Seal washer. I assume this cylinder is the missing link between the Gerdes and Cleveland's.

 

[Bartman]

that is super interesting Joe because that is probably exactly what it is, s

If you blow up the picture it is stamped on the cylinder. Gerdes A110-44. it appears to be the same as the Cleveland 10-54 with the exception that mine do not have the Stat-0-Seal washer between the shaft and the piston. But if my memory is correct Bobs Cleveland 10-54 also did not use the Stat-O-Seal washer. I assume this cylinder is the missing link between the Gerdes and Cleveland's.

That's interesting Joe and you're probably right about it being the missing link. I was looking at it on my phone and couldn't see the label stamped in it.