Cat 980c

Hello
I have made a post about this machine before so I'm not sure if I should have put this there or not. I am repairing the brakes on this they are wet. I have disassembled one side so far have removed all the friction and steels and they look good but my question is. Is there a trick on breaking down the brake piston with the springs and pins? the issue was that when using the brakes they would fill the diff. So it looks to be the piston seals correct? Just trying to look for the best way to tear it down. Thanks for a the help this far..

It would help if you posted a Serial Number, but basically the piston is held in place by 6 guide pins (18) that are spring-loaded. To release the piston it first has to be compressed slightly into the housing using a press or jack until the locking pins (19) loosen. At that point the locking pins can be slid out of the guide pins, ease off the weight of the press/jack gently and the piston will move up out of the housing. Reassembly is the reverse of disassembly. The attached is for a 980F but the procedure is pretty much the same for a 980C, it's just not very well explained in the 980C Manual.

This file from a newer model might be clearer.....

You need to pull plug 17 and push pin with spring 18 on it inward. You then slide pin 19 out of hole. To do this easily you can take one of the plug number 17 and drill and tap it to fit a 3/8 threaded rod. Put the plug in hole and turn rod in until lock pin 19 can be removed. You will have to buy one new plug 17 but you will have the tool to do the rest.

Perfect I appreciate the help. We were thinking of making a tool with the plug holes. And thanks Nige you are always a big help. I need to get my sis up and going again.

Johnpenwell said:

Perfect I appreciate the help. We were thinking of making a tool with the plug holes. And thanks Nige you are always a big help. I need to get my sis up and going again.

Click to expand...

That is a bit different than the brake on the 980 G's I more familiar with but if #17 is an oring type plug right behind each of the spring pins I would be thinking of getting a spare plug, probably just a standard hydrualic oring plug, and just drill and tap it for a 3/8-16 bolt and use that as a forcing screw to release each of the pins.

Just went back and noticed that Mobiltech already said almost the same thing!

The 980G's you could remove the brake piston/cylinder assembly as a unit and use a drill press to push down on the pins to remove the locking pin.