iDRY Vacuum Kilns

Sponsors:

Gearmatic 8A Master Control Rebuild

Started by Jdcrawlerdog, February 03, 2017, 10:58:45 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

Jdcrawlerdog

New to the forum and looking for some help. I recently rebuilt the master control (x-710) for a Gearmatic 8A winch. Everything is working fine on the clutch side. However, the brake cylinder is not getting any brake fluid past the plunger in the control, so there is no fluid getting to the brake slave cyclinder on the winch. I used two identical rebuild kits, one for each cylinder. There is no distinction between clutch or brake cylinders on the rebuild kits. The old brake cylinder in the control had a plunger with a hole through the center. The new cylinder rebuild kit's plunger does not. The folks at Davco said that the rebuild kits are correct and that there is a small hole in the cylinder that allows fluid to get behind the plunger. There is a hole in the clutch cylinder, but not on the brake cylinder. I checked an old control I have and it is identical, no hole in the brake cylinder. The brake cylinder has a bleed screw at the top. I have opened this up as well as taken the line fitting off. No fliuid, but the piston/plunder is moving fine and pushing air.

Short of re-using the old plunger, which is pretty rough, and finding a new o-ring for it, I am stumped. Any body rebuilt one recently with the same issue? Any thoughts would be appreciated. Need to get back in the woods. Thanks!

coxy

I could be wrong but on the 19 control the kits are not the same for brake and clutch  its been over 10 years since I rebuilt mine if its the old steal control that little hole may be plugged make shur you get that little plunger rod in the hole that works the brake

Ed_K

 Here's a blow up of a gearmatic 19 but I think its the same for an 8 also.



 

This shows the difference in length of the plungers.
Ed K

Jdcrawlerdog

Thanks Coxy and Ed. The clutch and the brake push rods are different lengths and I have the right push rod lined up with the right cylinder. The clutch cylinder has the small hole which is clean and working fine. The brake cylinder does not have the small hole, only the bleed screw. The control parts list shows two different part numbers for the brake and clutch cylinders, so they are different. Maybe the later series winches like the 19 used identical cylinders on the controller. Going to try going back to the old plunger and see what works. Trying to work back through sixty years of progress aint easy, but worth it. This thing could drag the Queen Mary out of the water if I had a way of holding down the JD 420 crawler that it is connected to. Small but effective.

Thanks for the help.

Jdcrawlerdog

Cleaned up the old plunger and found a new o-ring seal. Reassembled and bled the systems. Works as it should.

Looking at the 19 controller diagram, it is clear that the later controllers used identical brake and clutch cylinders. The Gearmatic 8a cylinders are different and the rebuild kit for the clutch will not work on the brake. Lesson learned!

coxy

funny thing I have a m control that i took off my 518 cat cause the oring on the handle was leaking so last night i took the ends off and they are different kits for brake and clutch  ???

Ed_K

 Glad you got it fixed. Now if someone else has this problem they will know that there is a difference in some models.
Ed K

Thank You Sponsors!