420 brake issue

Dr ken

Member
My mastercraft fork lift is a ford 420 my brakes work fine in reverse in forward they grab very hard and push the pedal back up at me to the point that they release then grab again over and over I can't stop it . I have removed the trumpet on one side everything looks good no scored steels and plenty of bronze material on the brake disk. After finding nothing looking wrong I looked at the way it operates and the linkage. I see that looking at other side the linkage is pulling down on the brake actuator this will cause the gap between the actuator stop and the big pin that stops the actuator from rotating to widen so that when it finally starts to apply the brakes it will rotate to the stop pushing my foot pedal back up and applying more pressure to the brakes makeing them grab very hard. Or am I over thinking this thing Remember the direction I am moving is opiset a normal tractor I had JD trans hydraulic fluid in it
 
(quoted from post at 16:37:41 04/07/19)
Shouldn't make any difference, the brakes on my tractor work the same weather I'm going forward or backing up.
So what do you think would make mine grabby in one direction only
 

Do the brakes activate when the pedals are less than half travel to the foot board?
Where the return springs under the foot board in place, I purchased a tractor that had one spring missing with the brakes worn out on that side.
Edit: Since your setting backwards on this tractor/forklift it must have some type of modified pedals and controls.
Can you post a photo of the pedals and controls.
Was there any adjustment left on the actuator control rod?

Here's a few specs to check.
Brake disc thickness 4.9mm
Steel disc thickness 2.69mm
Check the inner and outer housings for wear groves, also look for wear groves on the actuator half's.
The steel actuating balls should be 7/8" dia.
Check the actuator pockets the balls run in for uneven wear, and also how far up the tapered slot the balls have traveled.
If they've traveled over 3/4 way up the slots the brakes are worn out.
Check the torque pin for wear.

Typically noisy or grabby brakes on these tractors is caused by dirty oil or the wrong spec oil.
The John Deere J20A-JD303 oil you mentioned in another tread sounds like the cheap generic oil one picks up at TSC or Rural King.
I have found these oils very inconsistent and no longer use them, some states have outlawed the sell of these oils.
Look for oil that meets Ford 134 or John Deere J20C specs, the cheap oils say "recommended for" and usually don't meet the recommended specs.
 
. Thank you Destroked for the good info. I stopped at our local ford-newholland dealer today to order some parts he has a forklift that is a ford 420ish. as I suspected it has some crazy linkage setup I am sure the P.O. Of my mastercraft removed some vital pieces of linkage. With the pedals pushing the opiset way the linkage needs to hook to the bottom of the pedal below the pivot point this is pulling the brake actuator away from the
Pin that stops it from rotating so when applied the actuator rotates 1/2" or so pulling on the pedal and linkage causing the brakes to engage very hard and push my pedal back up at me the forklift I looked at today had an added arm and pivot point so the brake rod coming out of the axle was centered and pulling straight away from the actuator so when it does apply it isn't pulling the brake actuator away from the anchor point So now all I need to do is fabricate some special linkage
 

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