IH 684 Brakes

Hi again, still having trouble with the brakes on my 684 has anyone got any clues from the following symptoms.
When bled they are superb, hard pedal and great stopping power. When holding foot on the hard pedal, the pedal does not creep down at all which makes me think the wheel cylinder 'o' rings are ok (no seepage), & while ever the tractor is running they never fail.
Sometimes, after stopping the tractor for only a short period, the brakes have gone and take a lot of pumping & even then, need pumping each time I brake. However, sometimes after standing for a while, the pedal is solid straight away??? I just don't get it.
There is some dampness around the master cylinders/equaliser valve, but not really a major leak.
I suspected the equaliser valve, as there is some play in the pedal shaft & I thought this may be depressing the master cylinders unevenly, so I bolted the pedals together as the play was spreading the pedals apart even when clipped together & I won't need to slew so don't need independent breaking, but even now the brakes are either superb or useless, there's no middle ground. I need inspiration, I can't bleed them before every use although this seems to be the only way to be sure they will work. Anyone with ideas???? Thanks for reading.

Hi Stuart, see this link:
http://partstore.caseih.com/us/parts-search.html#epc::mr65455ar968196

Does your 684 have item #1 the reservoir for the brakes?

JimB
Untitled URL Link

No it doesn't have that. Is that what's referred to as the keep fill tank?

Yes, there should be a plastic reservoir up above the brake master cylinder to keep a supply of hydraulic oil for the brakes when engine is off.
So if the brakes are applied with engine off or there is a small leak the master cylinder will not be full of air. Similar to the older cars where the master cylinder has the brake fluid reservoir attached on top.

JimB

Is it possible to retro fit this tank?, and do you think this could be the issue?

Stuart, I am not sure this will fix your problem or not BUT IH installed the reservoirs on later models for a reason. CaseIH will want a small fortune for the parts likely. If you could get some tubing nipples and oil resistant tubing, you could make one out of a pint or quart motor oil container. It is a very difficult area to access.

JimB

That is the problem not having the tank. Also remove the third deal in the middle.

Stuart - I did a rebuild on the equ. valve on my 574, as I had the same problem, along with a fluid leak up in there. There is [was] a kit from IH for the equ valve, about 60.00 - To replace the valve was 700.00! People say JD parts are expensive, butI find they all are - Anyways, the kit did the trick, over two years now, I have brakes like when the tractor was new. Had to take out the battery, etc to get at it, but well worth it in the end.

Thanks Mike, I'll have a look for the seal kit.

Thanks Jim.

Hi Caterpillar guy, could you elaborate on 'the third deal in the middle'. Is this a typo?