70 Series Brake Troubles

1370rod · Jul 14, 2017

Any 770-1570 can have this brake problem if contaminated oil if left to circulate through the hyd system. Looking at the brake valve you will notice the inner spool in the LH port is not sticking out like the one in the RH port. It is stuck in because of metal getting passed the bypass valves in the filters of a 1070. The filters had not been serviced for years. Often when this occurs in the brake valve the powershift pilot spools are sticking also like this tractor. When the brake spools are stuck in, the brake with the problem will engage whenever backpressue is created in the system like turning the steering wheel. I found the source of some of the contamination. Rod.

Don L. · Jul 14, 2017

Example of several oil flow schematics pages I have. Kinda neat , to the right guy.
Don L.

fixerupper · Jul 14, 2017

That happened to a 1070 I had back in the 70's. It had transmission troubles under warranty. The dealer took the transmission-rear end down to a bare case and flushed till it was clean but the filings had done their damage to the master cylinder. First time it happened I was going down the road when it pulled down and smoked the brakes. Drove into a neighbor's place and chatted with the neighbor a bit. Got back in the tractor and took off running fine. The brakes smoked a few more times and after I replaced the brakes a couple times it went back to the dealer to figure out the problem. It was out of warranty by then but the dealer, Mather Implement Laurens, Iowa stood the labor and I stood the $400 bill for a new master cylinder. All was well after that. I kind of wish I would have kept that tractor but it wasn't big enough for the acres I farmed.

chuck machinist · Jul 14, 2017

OOHH!, I like that Don. CM

451 CUBES · Jul 14, 2017

Just went through one of these valves, same problem. Stuck boost spool. Put new seal kits in. Boy those teflon seals on the spools and pistons were infuriating until someone enlightened me to heat them in hot water, then slip them on, then put a hose clamp around the seal (over some thin plastic) on the spool to contract it back to diameter. I didn't know 70 series (lil ones) could have such good brakes after also putting in new disks.

olgentdc · Jul 15, 2017

me too ,.. need to keep that handy ,,

1370rod · Jul 15, 2017

The first time I installed one of the teflon rings I thought no way will I get these on with out damaging them, and I did not. Have since made tapered plastic sleeves for most all sizes that works great also. I wrap them tightly with electrical tape and let them sit a while and shrink back once installed. Rod.

casemagnum · Jul 17, 2017

I have a early 1070 gold demo. The brakes work good on the LH side but the RH side the pedal will not move or moves very little. Have to remember to only use the LH pedal when driving. So ONLY I drive it so no one gets hurt. Is the pedal sticking anyone think or is it in the valve on the dash or what? Any suggestions and thanks!! The park brake works at least but not the light on the dash to say it is on. Maybe bad switch on that too.

70 Series Brake Troubles

1370rod

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Don L.

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fixerupper

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chuck machinist

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451 CUBES

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olgentdc

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1370rod

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casemagnum

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