We have a 936F that the front brake reservoir has been going down and nothing leaking at the masters to the front axle so pretty sure its in the wheel brakes inside the housing. Going to make a plug so we can isolate which side or both is leaking and in the service book it shows 2 seals for that piston. Has anyone got some experience with these and have any tips on anything extra to look for before we tear into this? Going to check the friction disk thickness too and see if anything on that is in need of attention once it comes in.
-
Thank you for visiting HeavyEquipmentForums.com! Our objective is to provide industry professionals a place to gather to exchange questions, answers and ideas. We welcome you to register using the "Register" icon at the top of the page. We'd appreciate any help you can offer in spreading the word of our new site. The more members that join, the bigger resource for all to enjoy. Thank you!
Cat 936F internal front brake leak
- Thread starter MNorby
- Start date
Nige
Senior Member
If you identify which is the leaking side and then when you tear it apart you find the discs/plates need replacement then I strongly suggest that you consider doing the other side even if the piston seals are not leaking.
Also check the piston housing and piston for scoring. Score marks on either will take the new piston seals out in double quick time.
Also check the piston housing and piston for scoring. Score marks on either will take the new piston seals out in double quick time.
kshansen
Senior Member
- Joined
- Mar 11, 2012
- Messages
- 11,173
- Location
- Central New York, USA
- Occupation
- Retired Mechanic in Stone Quarry
Agree 100%. We had a 980G that made some bad noise when brakes were applied. One boss said "It just needs some of that additive" Well I knew what brakes sounded like that needed the "additive" and these were not going to be fixed that way. First they tried telling me just do the wheel that is making the noise. Well after the discs came out in pieces on the left rear they agreed that maybe we should "check" the right rear. That one had internal and external splined discs that had actually changed places! After a little more coercing they relented and let me pull the fronts apart. Not a single brake disc was even close to being reusable!
So unless you can see something obvious that was damaged at assembly time I would say at the minimum pull and reseal both brakes on the one axle. It's going to take only a little more time and you will have it blocked up anyhow so a few extra orings should be all that is needed. And make some notes so you can do the other axle in a few months in half the time!
Nige
Senior Member
Test the brake operating pressure at the wheels after you fix the piston seal leak. I have seen some loaders before where the pressure at the wheels was well in excess of spec. Piston seals don't last too long under those circumstances.
Nige
Senior Member
An unusual but very effective way of pulling the brake packs apart. Kudos.....
kshansen
Senior Member
- Joined
- Mar 11, 2012
- Messages
- 11,173
- Location
- Central New York, USA
- Occupation
- Retired Mechanic in Stone Quarry
Maybe just me but I would probably removed the top tire and rim assembly to make the upper section lighter to handle. And I can not help but be impressed at how clean the machine and shop are, that makes everything so much easier.
I'm assuming you did find a bad seal or two?
I'm assuming you did find a bad seal or two?
By leaving the top tire on was able to fork lift it on and off pretty easy. Aligning the shaft into the planetary was a little bit of a wiggle but not bad really with an extra hand. The outer seal on both sides was brittle and cracked out.
Nige
Senior Member
Did the steel separator plates in the brake packs show any signs of blueing..? Brittle piston seals are often an indication that the brakes have been pretty hot over an extended period of time and the separator plates blueing is usually the first indication.
Also were the housing and piston both OK with no evidence of scoring..?
The one plate had a tinge of blueing on the edge but overall looked good. The piston plate looked good except that backing ring in that outer seal looked to had almost melted to the sealing surface area in a spot, took a little elbow grease to clean that off.