JD 5303 Hydraulic brakes

Goatwhiskers · Dec 15, 2014

Any way to adjust? Left brake seems to be dragging. GW

Tx Jim · Dec 15, 2014

No adjustment available unless pedal is binding on pivot pin. Weak brake disc pull off springs can cause dragging. Solution is R&R rear axle housings/springs

jd110 · Dec 15, 2014

Actually there is an adjustment on the brake valve that I have seen cause brake drag. Items 20 and 21 is the brake pedal stop screws. On two different occasions I have found these adjusting screws loose and they slowly back out and prevent the pedal from returning all the way. If pedals are uneven, I would suspect this as the problem. Loosen the jam nut and turn the screw in until it no longer contacts the pedal. Then back out the screw until it contacts pedal and turn it out two more flats of the bolt head. The tighten the jam nut in that position.

Tx Jim · Dec 16, 2014

jd110
Thanks for correcting my mistake as I've never witnessed the bolts you referred to getting loose.
Jim

the old grind · Dec 16, 2014

Tx Jim said:
... Weak brake disc pull off springs can cause dragging. Solution is R&R rear axle housings/springs

... Right where I am with my 5210.

Cracking the bleeder didn't release the sticking LR brake & there's no way to jog the annular piston loose externally if you're 'there' too.

Spring & seal kits are out there and not too pricey. Book says either side ROPS base, fender(s), and fuel tank to be unbolted before removing housings. Also, piston(s) may have to come out to replace weak return springs, and new piston seals indicated if so. Pro'ly more time/labor than $$ if pistons, backing plates & friction discs are ok. Can share pics/info from manual to reinstall & set piston 'seating depth' on re-install. (Anyone with this issue can PM me anytime... already spent big $$ for factory manual ...)

btw, I suspect that if water enters the oil (hydro) it may settle in brake cyls and cause sticking, too. Much to look for once you're in there.

jd110 · Dec 23, 2014

the old grind said:
btw, I suspect that if water enters the oil (hydro) it may settle in brake cyls and cause sticking, too. Much to look for once you're in there.

If water contaminates the hydraulic oil, I would recommend replacing the disks when axles are off no matter how good they look. Water can cause brake lining to "swell"
causing brake drag and also can cause lining to "debond" from disks and fall off.

oldtimer 66 · Jan 14, 2015

Did this brake job a little over a year ago. New disks, springs and O-rings. My personal opinion is this. The O-rings that I took out , assume factory/were green which indicates there were Viton. The new O-rings were black probably nitrile. Viton like water and swells up but so does Nitrile. Every thing looked good even the old disks but we put everything in new. My personnel opinion is it was mainly that the old O-rings were swelled up. The

y were swelled up because of the moisture in the hydraulic fluid, as per jd110 comments above. Put it back together and everything worked fine. But I think all that was needed was new O-rings. It took a little over 5 hrs to do the job 1 person and one oldtimer 66.

Goatwhiskers · Jan 16, 2015

Got 'er done! We weren't smart enough to do both sides at once, put it back together and trouble showed up on the right side. Now we're experts on how to do this. Both discs had disintegrating linings, plus apparently the pistons weren't retracting fully. There has been moisture in the oil due to a cracked boot on the right shift lever, so there's one possibility. The other is that our oil supplier told us that 303 oil, which had been used earlier, does not have the proper additives and will cause the disc lining to disintegrate. No idea if that's true or not, but right now we're back in business. Thanks to everyone. GW