Specific Cure for Parking Brake Problem?

[jinman]

Success! Well. . .sort of. I got two out of three clear pictures. The one with the pawl mated to the wedge is slightly out of focus, but you can still see that even on my tractor the fit is not perfect. As a matter of fact, the pawl is not perpendicular to the wedge. If it were twisted just a little, it would fit much better. Anyhow, you can clearly see that my pawl teeth are not worn and that my wedge has no V-cut in it. That really has me baffled. Now, I want some others folks to crawl under their tractors and give us some feedback to see if their's is more like yours or mine. This is getting interesting.

EDIT: I also noticed my pawl has a half-moon shaped cutout that yours does not have. That must have been in the original part to allow clearance for the pawl to engage, but there is no reason for this cutout even on my tractor. On later parts, they must have eliminated the cutout on the pawl as your photos show, Charles.

 

[Ford850]

Charles, your wedge looks like someone cut that notch with a grinding wheel. The pawl teeth are worn a lot if it's from wear, no matter how soft the steel. I wonder if the previous owner tried to improve the design and really messed it up.
The problem I have with my PB is not the pawl or wedge. It is the wire that doesn't allow enough strength to pull the lock into position. It gets hung up at the handle end. If I lube it often it is not soo bad. The pawl and locking parts on mine are like new.

 

[Charles Billings]

Jinman & Ford850, Seeing Jinman's photo I am convinced that we have the same parking brake design with our NH TC45's. I thought that the groove was supposed to be there, but now I see that it was never intended to be there. I am now convinced that both the ratchet pawl and the wedge were made from very soft metal, and both are showing extreme wear. I can't solve my problem by replacing the ratchet pawl alone, the wedge also needs to be removed and a new one welded on. This is definitely a case of two defective parking brake parts causing a very early and predictable failure. Pictures speak louder than all the words that I have tried to use to describe my problem, and Jinman's pictures show me what things should look like if properly manufactured. Thanks for this clarification. Anyone else like to weigh in on this?

 

[RickB]

I have been watching this thread with interest, but have had no input because of a total lack of experience with this known problem, until today. I replaced the brake pedal and ratchet pawl on an early TC45D showing about 4400 hours. The brake would not lock under any circumstances due to wear on both parts.
The parts I removed were identical to Jinman's; 7 notches in the ratchet pawl and an angled lock tab welded to the pedal. These parts have substituted to the parts on Charles' tractor, 6 deeper notches in the pawl, and the lock tab weldment situated parallel to the pedal cross-shaft. I can't speak to the hardness issue at all, but these two design changes should make a significant difference in the effectiveness of the brake lock, especially as it relates to flexation of the platform during operator entry and exit. The bottom line for me is these parts should have been designed this way from day one.
My only comment relating to pawl and pedal wear, apart from the hardness issue which is somewhat unknown due to the vastly different service life of the parts in question is this: Both parts will last far longer if the pedal is depressed before the latch is pulled than if the latch is pulled and the pedal pressed after. Not pointing fingers or making accusations here, because I have never seen how either of you guys apply the brake lock. But it can't help but last longer if the pedal isn't dragged over every notch of the pawl until the brake is set.

 

[Charles Billings]

RickB, With your background as NH Service Tech I am believing what you are telling me. I didn't notice the suttle differences, like 7 versus 6 teeth. Do you think that the groove in my ratchet pawl was by design, or did wear cause it? My habit for setting the parking brake is to first press down hard on the brake pedal, and then pull up on the park brake handle. I really think that I am doing nothing that should have caused excessive wear, certainly nothing that accelerated it to equal that of the early TC45 with 4400 hours that you worked on. Remember that this tractor showed early signs of problems, from the first times I used it with only 190 hours. I am thinking that it must be a combination of design and parts hardness. If you had my tractor in your shop would you be able to fix it so that it would work and last like Jinman's? My real question is when I take it to my local service shop how do I make sure that they don't replace it with the same parts and design that caused the origianl failure within the first couple hundred hours of use?

Jinman, How often do you use your brakes. The paint is hardly scratched off on the lock tab? I am assuming that you use it as often as I do, certainly anytime I am off the tractor and it is running, also anytime there is an incline even if the tractor is turned off. What year is your TC45?

 

[RickB]

If you had my tractor in your shop would you be able to fix it so that it would work and last like Jinman's? My real question is when I take it to my local service shop how do I make sure that they don't replace it with the same parts and design that caused the origianl failure within the first couple hundred hours of use?

I did this repair at the customer's location; about 30 miles from the dealership. So far as I know, I installed the same parts on that 45D as the ones yours was built with. Makes you feel good, doesn't it?

The lock tab welded to your pedal has an incredible amount of wear. If it were my tractor, before I dropped over $100 on a new pedal, I'd experiment with a mig welder. Fill up the wear groove and grind the proper profile back in the tab. I probably would cough up the $60 for a new pawl. The pawl is retained on its pivot with an E clip. I didn't remove the bracket the pawl pivots on, I just popped the clip off and removed the cotter pin from the operating rod, and the connector from the switch.

Your pedal looks about 10 times worse than the one I took off the 4400 hour 45D. I'd like to know why it is worn so bad. Your pawl actually looks better than your pedal.

Edti: Just to be clear, the tab welded to your pedal had absolutely no "groove" in it when new.

 

[Charles Billings]

RickB, I really appreciate you taking the time to review this debate and provide a technical analysis and some repair suggestions!

 

[jinman]

Jinman, How often do you use your brakes. The paint is hardly scratched off on the lock tab? I am assuming that you use it as often as I do, certainly anytime I am off the tractor and it is running, also anytime there is an incline even if the tractor is turned off. What year is your TC45?

Charles, my tractor was purchased in February of 2001.

I use my parking brake a lot to hook up implements or when I get off the tractor on any incline whether the engine is running or not. I normally operate with my brake pedals split for differential braking, so normally my parking brake only sets the right-rear brake. I can always tell when my wife has been on the tractor, because the pedals are tied together with the tab and both pedals are set when she parks the tractor. So I'd say we use that park brake often.

RickB, thanks for weighing in. There's nothing like the experience of someone who sees lots of tractors. We all normally see only one. We tend to think all tractors are the same as ours, but this thread shows how that can be a wrong assumption.

 

[Charles Billings]

RickB & Jinman: Today, I was going by a Kubota dealer and saw a lone blue tractor there, so I stopped with the idea of checking out its parking brake. It turned out that it was a TC55, the same year as mine, a 2006. It had the same design as my TC45, not a big surprise. Its parking brake was in pristine condition, but then I checked the hours on the tractor--it had 38 hours. I inquired about the price; $21,500 with 2 rear remotes, 18LA loader with large quick attach bucket, and a rear 5 or 6 pin electrical jack (what is that all about?). Looks like a deal! However, let me get back to the parking brake issue. I looked at mine again, and hope that I can get some new ratchet pawl and fix it myself. Changing out the parking ratchet pawl looks straight forward, as RickB described. Getting the parking brake off so I can "seal" over the groove in the engagement tab that is welded to the pedal shaft is not as straight forward. It looks like I would need to do the welding and grinding with the pedal still in place. That is, unless I want to remove the Woods backhoe subframe. Some pictures, below. Is nothing ever simple? RickB, is brazing and grinding the tab with the brake pedal in place something that you would attempt--that is, should I attempt that? I just went out and purchased a grinder, hoping to do this, and hope I can convince a neighbor with a welder to do the brazing. When I look at that groove in the engagement tab, it suggests just how soft that metal must be. If I tried to do that with a blunt saw I can't believe that I could have done a better job of hacking into it.

 

[RickB]

Brazing yields a soft metal deposit that probably would not last. My suggestion to use a MIG weld was based on my experience that the average MIG wire leaves a relatively hard deposit and the process can provide some hardening to the parent material.
Even with just a 16LA loader I had to drop the loader support running back to the rear axle in order to remove the pedals.
The amount of work involved is usually linear to the importance of doing it right.