12H, now I need park brake info

[Bala]

I have realized today that this grader has no park brake at all,

Are there any trick to removing the park brake

thanks

[lonkinggroup]

I am confused....., do you mean you want to install a park brake in your grader or remove it ? It is not safe if there is no park brake in the machine after all.

[Bala]

Sorry, I will explain, this unit had problems with the air system a little while ago, it had a stuck valve in the compressor and was not making any air. i thought at the time it was strange that they were able to bring it back to the workshop without air as it has air brakes, but I obviously had other things on my mind and forgot that detail.
I would say what has happened it when it had no air the driver(as I dont term him an operator) has gone to drive and it stalled so he has just used first gear and more power and it has come good. Come good means the park brake is now burnt out so it will drive!!

So it has a brake brake, it just does not work at all so i need to pull it out and check for damage. I am assuming it is a multi plate set up?and hopefully just burnt out the discs.

As I have not had the park brake out of one of these I am asking if their are any tricks when doing so.

[rare ss]

i've never done one but i seem to remember hearing they are abit of a pain to do

[CAT793]

This is a question not a statement:- arnt they a maxi over a clutch pack in the Tranny? Or is that only on 16...

I have done plenty of 16 and it is check the system air pressure/gov valve/air dryer purge valve then the operation of the maxi and quick dump valve, adjust the rod to the Max.....still no luck it is tranny out and strip. Lever and ball bearings on a ramp used to lock a clutch pack.

[Bala]

this has an air line direct into the front of the transmission, I have no idea what happens inside, even with the air line off the park brake does not hold at all.

[Fred]

With the "H" it is heaps easier to repair park brake then on a good ol "G". No need to remove trans.
That front housing you are looking at comes of after you take the jack shaft of between diff and trans.
Pretty heavy but ok to lift by yourself just dont drop it.

[Nige]

He'll have burnt up the park brake. Engage 1st gear, stomp on the accelerator, and you can drive straight through them. We had no end of trouble with operators burning park brakes on 16's until we did a bit of a mod and linked the air systems for the service brakes and the park brake together. Then if the air pressure woasn't up the service brakes stayed on as well and the mahcine moved nowhere. It was also funny watching an operator hit the park brake while still moving (remember most of them used to operate standing up in those days)- it usually stopped the machine so hard he would be wiping his nose off the windshield.

I'll e-mail you the remove and install, plus D&A procedure for the parking brake. Oh, and the parts list as well.

[smoothoperator]

Caterpillar made updates/improvements in the o-ring material that seals the parking brake release piston. (It's huge, but I think it's still called a piston)
The dealers parts system should automatically supply you with the newest and best parts available. It helps to have a couple of guide dowel pins cut to help with removal and installation.

smoothoperator

[Nige]

I just checked SIS, no mention of the seal but the piston was upgraded in December 2008 - supposedly a change of material to assist in preventing corrosion of the piston. The Parts system will automatically supply the new part number if the old one is ordered.

[Bala]

It helps to have a couple of guide dowel pins cut to help with removal and installation.

Good tip, thanks for that,

Nige sent me a parts list but i just used the item numbers and Qtys for my order, send a pic of the serial number plate and cat dealer can work out numbers,.

I think I should put a set of dc powered air horns in the cab behind the drivers head and connect them up to the gear lever and low air warning. Next time it has an air problem and he tries to drive over the park brake it will blast him out of the cab!!!!!!!!!!!!!!!!!!!!!!

[Nige]

Better still, do the mod we did and interconnect the parking & service brake air systems. Needs a couple of valves and some hoses but not hard to do. With that modification done, basically until the air comes up to at least 100psi the service brakes won't release - ergo the machine will not move.

[Bala]

I thought about that, if i understand the system correctly as the service brakes require air pressure to activate this would mean leaving the service brakes pressurized in ark and when the engine is off. This machine may sit for weeks at times and I was wondering about long term leaving the service brakes pressurized.

But another reason I will not bother is that I am leaving in 3 weeks!!.

But the main reason is, why should I need to do so (yes I know I really need to!!) When the simple fact is that the operator should not try to move the machine ever while the Red flashing light is on, and in the case of low air, the Red flashing light and a bloody loud beeping horn.

When first got this machine it come off the barge and was moved, next day I get the call that the warning light and beeper are staying on. It was over half an hour later that I got to the machine and they still had is running, it was lucky it was just an open air bleep tap and not oil or water problems.

[Bala]

I was to be finished here but had to fly out as my dad was Ill so then had to come back for a few weeks, Ifly out Sunday.

finally fitting the new brake discs, as there is a lot of brake material that has come off is there a suction screen in the trans on the 12H?

[Nige]

You need to go both into the bottom of the diff housing to get all the material out. That's where most of it should be. The transmission suction screen should be in the line coming to the transmission pump from the diff.