Gearmatic winch on 420c etc.

[Paul Buhler]

Hi: I'm new to this board and the posting format, so please forgive any mistakes while I'm learning. Anyway, I recently bought a dead 1957-58 420c, with 5 roll undercarriage, 6 way (manual) inside blade, a well made ROPS, and a Gearmatic winch (8a?). After tinkering and repairing a few things I got it to run, and so far It seems to be reasonably sound, The undercarriage is in particularly good shape considering its age, and it steers and moves as it's supposed to. I pushed some dirt with it today and it seems to behave. It has some blow by in the engine, which I may have to deal with sooner or later. I got the winch to winch in ok and the brake locks up properly and releases enough for winching, but I can't get it to free spool (I tried chaining it to a tree and putting it in freespool too) The control lever has oil on both sides when I crack the fittings, but the actuator attached to a shaft with a spring by the brake band end of the winch doesn't move when I try to move the control lever. When I cracked the fitting, the lever moved as expected, so I suspect that there is something going on inside the actuator, but I didn't want to dig in blind. I can't find a schematic of the winch I have. I loosened the brake cover bolts in preparation for removing it to inspect the brake bands, but I haven't opened the housing yet. Does any one have any experience with these winches and ideas on what I might try? Thanks. Paul

[Lavoy]

The brake on an 8A is always applied, even when winching in, it is just not self applying in that direction. To get the cable to spool out, you have to push the lever all the way in the opposite direction until it overcenters, that is supposed to release the brake. Take the tin side cover off and you will be able to see if it is releasing the brake when you do this. If not, you have air in the line, lack of fluid, or fluid bypassing somewhere.
Lavoy

[Paul Buhler]

Thanks for the info. I'll check for air. I opened the inspection port and it looks good inside by the band. I figured out how to do a search here and found a lot of good info. I downloaded the Gearmatic service manual (BG8a). It says to use 20 wt oil, but as soon as I filled the reservoir, I saw that you're supposed to use brake fluid. I'm assuming that means there are rubber seals that will be harmed by oil, so I'll drain, refill, and bleed tomorrow up to the slave. Paul

[Paul Buhler]

I got a lot of good info on winches by using the search engine so maybe some one else will benefit from my experience. I was able to track why the gearmatic winch wouldn't free spool. The slave cylinder which pushes down on the shaft to the brake band was frozen/rusted/corroded - you get the idea. It is easy to remove and once in my hand, I was able to work on cleaning up the exposed rust and I put brake fluid into the cylinder to get things to soften. I could see a coil spring inside and figured that the piston was frozen. I put a size matched socket into the exposed part of the slave and started by tapping on it to get some oil into any joints. eventually I took a large C clamp and pressed the piston deeper into the slave which really allowed me to clean things up and put the brake fluid to it. I used a 1/4" wooden dowel to push the piston out, and the socket to push it in until the piston moved pretty easily. Once cleaned up, it went back together easily. I filled it with brake fluid and worked back to the controller bleeding out the air as I went. Now that the piston could move, the brake released as designed and all is well.
The moral? Boy I wish modern machines were designed to fix like these machines. This dozer is 50 years old, and It responds really well to TLC. While I was at it, I removed the brake side cover to take a look around. I got lucky and all the cap screws came out and I was able to clean out the threaded holes for jacking off the cover. I used a LOT of TLC working the cover off the big center bearing; a little turn of the screw here, a tappity tap there, more turning, some loosening and re-aligning to keep the cover square to the bearing and eventually it slid off with out breaking - whew. By the way, at some point the whole cover spins around on the bearing making it easier to reposition the jacking screws and tap on the cover in different places. I hope my experience helps someone else.

[Gil]

I just purchased a manual for the Gearmatic 8A from an eBay auction. When you mentioned that you had found one online I assume you meant the BG8A hydraulic winch manual. If the 8A manual would help you out I could send you a Xerox copy if you send me your address.

I would scan it but the Vista gods apparently do not like my scanner and they refuse to cooperate with it. Perhaps one of the guys that scans and converts manuals to CD will read this and offer to convert it to a pdf file so it could be shared by the group. Or maybe someone has already done that. The manual I have is only about a dozen pages long and there maybe a more extensive manual available somewhere. Still it has some good line diagrams and it is better than looking inside an inspection hole with a flashlight.

[Davie Sprocket]

Gil i've been hunting for the 8a manual for sometime now, if you do get a pdf i would be greatly interested in having a copy.

Have a good one.

Dave

[Lowly]

Hey all,

Have we found a way to share a manual for a gearmatic 8A? I downloaded one for a model 9 from Paccar/Gearmatic but no luck on the 8A. Just found this site and am pretty excited. I have a 1956 420C, four roller with an 8A winch and an inside blade.

[Gil]

I have a copy of a 23 page Gearmatic 8A manual which Paul Buhler converted to a .pdf file for me. I do not know if Lavoy knows of a way to post the .pdf on this web site. If there is a way I could forward the document. In the alternative, I could email a copy to you if you send me your email address. Click on the pm (private message) link at the bottom of this message.

[Lavoy]

I guess I don't know if there is a way to post it, one of the more computer literate guys will have to answer that. You should be able to send the file in an attachment in an e-mail.
Lavoy