368293R91 Brake Actuator, F504, Issues... Pictures...

charles todd · Jan 26, 2009

I have had no problems prior with my brakes, both work... Worked until this happened. I stepped down on the LH brake to "park" and I heard a "POP". The actuator rod end with the ball attached shot out from under the tractor. Pictures below.

Has anyone had this happen before? I have not tore into it yet to see if the actuator hung up. The brake is not dragging. It looks like the rod had been cracked for a while and finally failed. Is it possible to buy just the actuating rod only or just the entire 368293R91 assembly.

I will know more once I tear it down and examine. Do these actuators become worn to the point that they need replaced? Or could this just be a result of the rod being stressed and cracked years ago and just failed.

[b:237840f6f3]I strongly think I only need the threaded rod that connects to the actuator, I have the nut and pivot ball.[/b:237840f6f3]

I am trying to save steps here. Not that I am lazy, but I know there are guys with parts, parts tractors, and tractor parts stores that frequent the board. Maybe someone has a rod or actuator for sale or trade.

Thanks,

Charles

John Athey · Jan 26, 2009

Charles......yes you can just buy the rod, but you better buy the part that screws on the rod to adjust the brake tension also. You will have a hard time of getting it off the broken rod.

the tractor vet · Jan 26, 2009

Just hate when that happens , and your not the first to have it happen to . I have replaced them with new and i have welded them and rethreaded them also . Just comes down to the fact that she was used to much when new.

charles todd · Jan 26, 2009

So when I tear into it, could I reuse the clevis end and pivot nut between a piece of NF GR 8 all-thread?

Charles

the tractor vet · Jan 26, 2009

Well yea you can but i am cheap and just welded it back together . But i can weld vary well . I stayed in practice welding my 2300 AC disc gang bolts back together . There are times when ya don't have the time to drop everything and run and get a part and the welder is there and ya can glue it back together and be back in the field before ya get to the dealer only to find out that OH we don't have that part and it will take three days to get here , SO some lincoln ready bolt gets the job back up and running while you then can order the part the next time you just happen to be at the dealer .

John Tomicek · Jan 26, 2009

Ihad the same problem. That ball will come off of
the rod. Just get a high strength bolt the same size
and screw it into the clevis.

charles todd · Jan 26, 2009

I like to think I am a pretty good weldor. I go WAY BACK with the 7018 Lo-Hy. I am going to tear it down tomorrow after work an see what I've got. It has been a while since I was inside the disk brakes. I do not remember if the threaded (partialy on the exposed) rod threads into the clevis or what. I plan to "borrow" some 3/8" NF Grade 8 all-thread from the "big store" and go from there. If I have to I will drill and tap the clevis and use some red loctite to secure it in place. Then I will have a threaded rod and not have to run my die nut through a weld (broke in the threads). Fortunatly I found the pivot nut.

Charles

bc · Jan 26, 2009

Charles, it kinda looks like you might have used up about all your adjustment. Probably want to check your pad thicknesses when you get it off. Lay a straight edge across your brake housing and use feeler guages to see how much gap you have as a reference (at some point you may have to machine some off along with replacing the pads). I'm not sure the actuator disks actually wear that much. More wear on the surface on the inside of the housing and on the rear end housing. Lay a straight edge on that surface to check it for wear.

scotc · Jan 27, 2009

If that's the same setup as the m/300/400, that rod should be something like a fine-threaded 7/16 bolt, with a few washers, a spring, that ball, then a nut to hold it all together so it stays together in the case of that bolt breaking. You should be able to grab whats left and spin it out with vice grips or channellocks and spin the new one in. The ones on my SM bend downward wherever I adjust them to. If you adjust them after use and the bolt it bent, make sure the bend is the same way when your done or it's off to the deler for another, sometime soon.

Janicholson · Jan 27, 2009

The reason it broke!
The ball becomes worn into the shape of the socket and sticks in place. this then forces bending to take place on the bolt shank. I agree with the use of a grade 8 or titanium bolt to replace the threaded part. Getting threads long enough to do the job will be the hard part. Ready rod is usually grade 5 and might work, but is tough to find in fine thread. Lube the ball with moly grease when assembling it to reduce friction. JimN

karl f · Jan 27, 2009

if you want to try a clevis that is already tapped for a stud or threaded rod, there is a type of product called "brake yokes."
Dorman makes some, some autoparts stores can get them.
for example, a 3/8" pin hole, with 3/8-24 thread would be part number 125-004.
the length is about 2.5 inches though, so might take up too much space.

Also what can snap them is trying to turn the ball when it is rusted in place. I broke one off the 656 with just the wrench, so it"s possible that yours was twisted just enough to crack at one time, and today was the finishing touch.

karl f

charles todd · Jan 27, 2009

Thanks for the suggestions guys. I have still yet to tear into it this evening, planning on tommorow. I did cut 3 lengths of 3/8-24 all thread "ready-rod" at work. It is true black oxide Grade 8 or 9.8, it is hard stuff. I do not remember what the clevis looks like or if it has female threads. If not I will drill and tap to 3/8-24. If modifications are needed I plan to do both sides to keep it consistant. I think I have the broken rod covered.

Now, for the $64,000 question... For the 504 disk brakes, what is the minimum disk thickness? I know they are well aged and well used. When I do not use them for a while I have to "ride" them to clear the surface rust, ect to bring them back to par. I am sure that 4 new disk would not be a bad idea.

I have been told by an old IH mechanic to take the disk and cut additional grooves with a grinder to help them clear out to prevent glaze. Pretty much he said get aggressive with them. I know they have some grooves as manufactured. Cutting additional grooves seems like I am removing and wasting expensive material (bout $65 - $90 for 4).

Thanks in advance,

Charles

bc · Jan 27, 2009

I'm not sure there is a minimum disk thickness. Go until you run out of adjustment. If they are down to flat with the grooves and you still have adjustment, I suppose you could cut the original grooves a little deeper. There is still pad where the grooves are.

New pads are a hair over 1/2" thick. Maybe close to about 9/16".

If you got adjustment and pad left, I'd say your lucky. Those actuators only spread so much. At some point new pads won't work and you have to machine off some of the housing surface.

Part of the reason it may have broke (maybe) is that you are out of adjustment. The two actuator rods from the clevis to the disks pull tight against the housing as you adjust the ball up too much. Then the actuator disk spread has reached its limit. You will see that when you get the housing off. Let us know.

Janicholson · Jan 28, 2009

They are "clutch disks" they just stop instead of go. So the thickness should be determined to be OK if the geometry of the expandes is Ok. They do not do well in the last 1/4 of their travel, the pull links are at a steep angle and less effective. Some have found that the outer housing needs to be milled/ground to compensate for surface wear so new disks can be used with near original clearance and performance. Milling the mating surface of the outer housing brings the fixed friction surfaces closer together. JimN

368293R91 Brake Actuator, F504, Issues... Pictures...

charles todd

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John Athey

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the tractor vet

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charles todd

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the tractor vet

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John Tomicek

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charles todd

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bc

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scotc

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Janicholson

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karl f

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charles todd

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bc

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Janicholson

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