J.D. 790 no parking brake

[BeaverIslander]

I just finished roughing up the brake shoes and thoroughly cleaning with brake cleaner as they were all glassed over. The brakes were squealing pretty bad and I was hoping it would quiet them down PLUS somehow magically fix the parking brake which hasn't work since I bought the tractor 6 or so years ago.

Anyway, long story short the brakes work as they should and are quiet. (and I'm thankful for that!)

However the parking brake still doesn't work and I can't find any videos or directions on how they should operate. View attachment 164827View attachment 164828View attachment 164829

 

[BeaverIslander]

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[BeaverIslander]

I'll try to loosen them tomorrow, maybe the pedal just needs a little slack to engage.

 

[Jim.ME]

I gave you a link to the parts book that has drawings of all this in your previous thread about brake parts.

The pawls do not appear worn out to me in your pictures.

Look to see that all the parts in the parts book are there. In your first picture it looks to me like the slot is against the pin at the wrong end of the slot for the released position. That means it is not getting the correct amount of travel forward to engage the locking bar. From your pictures I am wondering if the spring # 25 is installed wrong or someone assembled something else wrong. The pawl cam (aka brake cable?) should be pushed part way to the position it is in by the lever when the lever is push down to release the pedals and moved toward to engage the locking tab when the pedals are pushed down (applying the brakes) and the lever is lifted. Most ratcheting pawls like that have some light spring tension pushing them against the lock bar, so they ratchet by the lock bar if you push the pedals down harder for more holding power.

Do you have the service manual for your tractor? John Deere publication number TM1470 for tractors with serial numbers 190064 to 592445. Tractors 592446 to 7900001 and tractors serial number 790001and after use John Deere publication number TM2088. I would expect some info on that system in the technical manual.

 

[BeaverIslander]

I have the TM2088 February 2004 TECHNICAL MANUAL.

I saw that part put when it described it as a "cable" figured something was wrong.

Thank you for replying Jim.

I took the 4 pics down as I didn't want to hog up all the space here.... figured they weren't that useful anyway..

 

[Jim.ME]

I have the TM2088 February 2004 TECHNICAL MANUAL.

I saw that part put when it described it as a "cable" figured something was wrong.

Thank you for replying Jim.

I took the 4 pics down as I didn't want to hog up all the space here.... figured they weren't that useful anyway..

No need to take pictures down, most like to see them. If you want to take less space in a post insert them as thumbnails.

The parts book calls that pawl bar a brake cable as well, who knows what the person making that drawing was thinking.

 

[BeaverIslander]

I found a solution to my parking brake issue and it was simple once I spent more time underneath the tractor.
The brake peddles were adjusted to go down the recommended 1" or so before pressure was felt, but that didn't allow them to go down far enough for the "pawl" to catch.
By backing off the turnbuckles on the brake rods the "pawl" was then able to "engage" (then I did the other side to match.) The brake pedals are lower than what they were..... but whatever it takes I guess.

Anyone without a parking break on a 790 may want to check it out.... it's pretty easy to understand once you know what to look for.

 

[BeaverIslander]

I have the TM2088 February 2004 TECHNICAL MANUAL.

I saw that part put when it described it as a "cable" figured something was wrong.

Thank you for replying Jim.

I took the 4 pics down as I didn't want to hog up all the space here.... figured they weren't that useful anyway..

And thank you to Jim.ME for helping me out!