Specific Cure for Parking Brake Problem?

[bluehog]

I know this is an old thread... but many of us who still have this style ebrake assembly can and will suffer from this hazard. I have/had the same ebrake failure that has been described here, I had a runaway tractor on a downhill slope.

My wife and I were hand loading large exposed & loose rock into the bucket for relocation on our NM lot. With the bucket partially full I moved the tractor to the next area. With my TC35D still running and pointing downhill with the bucket about a foot off the ground as to keep the already loaded rock inside, I set the securely engaged ebrake. I jumped off the left side of the tractor to assist in loading more rock. When my weight left the platform the ebrake completely disengaged! My wife was just about to step in front of the bucket when I screamed at her. I attempted to get back onto the moving tractor and missed my footing in the foot cradle and luckily grabbed the steering wheel in my failed attempt to jump on. Thanks to the power steering this turned the tractor to the left just enough to send it directly into a 6" diameter trunk Juniper tree about 25 feet away. It flattened the tree to the ground tearing out the roots and all, but it stopped it from going several hundred feet down the hill which who knows what would have happened! I cannot believe how fast this tractor took off once it was disengaged! I know it weighs over 8000# with the backhoe... but wholly crap it was moving!

Major lesson learned... I feel like a complete idiot having done this in my hurry to complete our project I jeopardized my and my wife's lives and the investment into our tractor. Things have not been the same since... which is a good thing! Safety first... it's just hard sometimes when you just have to do one little thing to force yourself to take every precaution.

So upon return from this adventure I took a serious look at the ebrake assembly. Which I will explain in the next post.

 

[paine]

I know this is an old thread... but many of us who still have this style ebrake assembly can and will suffer from this hazard. I have/had the same ebrake failure that has been described here, I had a runaway tractor on a downhill slope. My wife and I were hand loading large exposed & loose rock into the bucket for relocation on our NM lot. With the bucket partially full I moved the tractor to the next area. With my TC35D still running and pointing downhill with the bucket about a foot off the ground as to keep the already loaded rock inside, I set the securely engaged ebrake. I jumped off the left side of the tractor to assist in loading more rock. When my weight left the platform the ebrake completely disengaged! My wife was just about to step in front of the bucket when I screamed at her. I attempted to get back onto the moving tractor and missed my footing in the foot cradle and luckily grabbed the steering wheel in my failed attempt to jump on. Thanks to the power steering this turned the tractor to the left just enough to send it directly into a 6" diameter trunk Juniper tree about 25 feet away. It flattened the tree to the ground tearing out the roots and all, but it stopped it from going several hundred feet down the hill which who knows what would have happened! I cannot believe how fast this tractor took off once it was disengaged! I know it weighs over 8000# with the backhoe... but wholly crap it was moving! Major lesson learned... I feel like a complete idiot having done this in my hurry to complete our project I jeopardized my and my wife's lives and the investment into our tractor. Things have not been the same since... which is a good thing! Safety first... it's just hard sometimes when you just have to do one little thing to force yourself to take every precaution. So upon return from this adventure I took a serious look at the ebrake assembly. Which I will explain in the next post.

I don't even have a step on my DX33 (TC33DA) but I am interested in your next post...

 

[bluehog]

Here is what I found when I investigated my ebrake assembly. These pics are taken looking from the ground up and show that the teeth on the ratchet pawl had created a void at their contact with the metal bar attached to the brake pedal. The alignment of the ratchet pawl was not and never was square/perpendicular with the engagement of the brake pedal. This off center contact had worn an area that finally failed/warn causing the disengagement of the ebrake when I stepped off the left side platform.

After removing the ratchet pawl you can see the rounded edges of the teeth in these views

 

[bluehog]

To temporarily fix the problem I have repaired the ratchet teeth using a jewelers file to reshape without creating any rounded edges

Then to create a better alignment with the brake wedge block I used a couple crescent wrenches to twist area of the ratchet teeth to correct the misalignment. What I was surprised about was how easily this twisted! I made sure to bend the area above the ratchet teeth so as to maintain all the teeth inline... if you attempt this do not bend in a way that the teeth are not inline and parallel with each other! This metal bracket is quite weak and definitely not heat treated or hardened.

When I reinstalled I was still a little out of alignment. So I adjusted further to get better engagement. Note the wrench is above the teeth maintaining them all inline... again do not bend so the teeth are not parallel to each other!

The realignment placed the teeth in a new contact area of the pedal wedge block so I did not need to repair the worn area.

In the 2nd to last pic you can see where the teeth had originally engaged
with the fixed pedal wedge block (worn away area where teeth had eroded the metal). This also shows how much I twisted the Ratchet pawl to achieve best mechanical contact.

 

[bluehog]

I have used the ebrake without issue, but I do not trust the ratchet pawl. So here is what I am doing to correct it... I ordered a replacement from Messick's At $63.55 + shipping.



The replacement part is a bit different than the stock one with only 6 teeth that appear to be slightly deeper. The new unit is missing the half-moon cutout just above the teeth which will make it more difficult if it is necessary to straighten alignment with the pedal wedge block. I do not have the tractor handy with me so I will need to attempt the repair in NM when I return there in a couple weeks.

For those attempting replacement or repair... the process is pretty straight forward. Although I did not take notes, I did take some pics, so as I remember it. SAFETY should be your first concern. Make sure you are on level ground, tractor is in gear, block the wheels, etc.

Step 1 - remove the ratchet pawl pivot bracket which is held on by 2 hex head bolts (seen here at the top of the pic)

Step 2 - remove the "e-clip" from the bracket pivot shaft

Step 3 - remove the ratchet pawl from the bracket

Step 4 - remove the electrical connector from the ebrake safety switch

Step 5 - remove the cotter pin & washer from the linkage bar

Step 6 - if replacing remove the safety switch

Assembly is in reverse.

 

[paine]

Thanks for the update, I have not yet had any issues with mine but I am going to inspect it before something happens.

I did how ever "over apply" the brake once and the tooth bar went over the the wedge and I hade to help it back into place.