Specific Cure for Parking Brake Problem?

[jinman]

Yesterday, with some time for goofing off, I crawled under my tractor and looked at this parking brake issue. As I suspected, my teeth on my pawl are not worn whatsoever. I could not get my brake to release by stepping on the step or flexing the platform. Go figure? I did notice several issues with the brake. For one, the brake works off the right brake pedal only. If you don't have the pedals tied together, the left brake cannot be set. Also the right arm has a 3/8" piece of flat stock welded to it that is ground down with a bevel from the bottom side, but flat on the top. This makes a point to engage the pawl. I've created a drawing attached that shows this piece. It engages the pawl, but the shape and size of the teeth on the pawl do not allow this piece to fully engage. What I recommend for anyone having a problme is to do a little filing or grinding to remove the tooth below where you normally set the brake and make the tooth above somewhat deeper so the pawl is engaged much more substantially. If mine ever starts slipping, this is exactly what I will do.

I came up with several other solutions, but this by far the easiest to accomplish and I think it will produce the best results. It's certainly cheaper than spending $60 on a new pawl that is doomed to fail just like the first one.

 

[SPYDERLK]

I think you would want to change the tip profile of the blue part.
larry

 

[Hematite]

I think you would want to change the tip profile of the blue part.
larry

That's what I thought, also.

 

[Charles Billings]

Jinman, Thanks for taking the time to crawl under your tractor to get a look, and for taking the time to analyze and report on a reasonable fix. My TC45DA is a 2006 model with about 550 hours. It also has a flat plate welded to the brake pedal. However, this plate has a V-groove cut into it, which is supposed to engage and seat into the ratchet pawl. Unless I misuderstand the design on your TC45, we don't have exactly the same thing. Unlike yours, my ratchet has worn and rounded teeth (the V-groove looks fine). I wonder why yours has stood up so well, considering that you have about 3 times more hours. Could it be the design change, or is it possible that your ratchet pawl had been hardened, and mine had not. There must be a dramatic difference, because it sounds like your parking brake looks almost new, and mine is visibly worn, and has failed.

 

[jinman]

I wonder why yours has stood up so well, considering that you have about 3 times more hours. Could it be the design change, or is it possible that your ratchet pawl had been hardened, and mine had not. There must be a dramatic difference, because it sounds like your parking brake looks almost new, and mine is visibly worn, and has failed.

That is exactly what I am wondering, but my brake components look just like the drawings on the NH website. Perhaps I should take the time to crawl under there and take a few pictures. I can't help you with failures, but perhaps I can help by showing how my components look. I was pretty surprised to see mine looks almost new. However, the underside of my operator's platform is quite rusty and that has concerned me from the beginning. That said, I've never experienced any parking brake problems and I'm at a loss to explain why. I'll get some photos posted soon.

 

[Charles Billings]

Jinman, Thanks for offering to get under there and take some pictures. I will try to do the same and post them as well so that we have a good comparison. Actually, maybe I will get my 13 year old son to get under there. He will be able to focus better in dim light--after about age 45 focus in dim light gets more difficult and I am 20 years removed from that. From your prior description your design does not have a V-groove attached to the foot pedal that engages with the ratchet. Is that correct?

 

[jinman]

Jinman, Thanks for offering to get under there and take some pictures. I will try to do the same and post them as well so that we have a good comparison. Actually, maybe I will get my 13 year old son to get under there. He will be able to focus better in dim light--after about age 45 focus in dim light gets more difficult and I am 20 years removed from that. From your prior description your design does not have a V-groove attached to the foot pedal that engages with the ratchet. Is that correct?

Mine is not a ">" shape. It is flat on top and angled like this"/" on the mating face so that the flat does not tend to slip out of the grooves on the pawl. However, since you can depress the pedals more or less and change the angle of the pedal relative to the pawl, it is not a perfect fit into the pawl's grooves and that's why I suggested cutting the grooves deeper.

 

[Charles Billings]

Jinman,

I think I didn't explain the V-Groove in my NH TC45 very well. The ratchet engages with this V-Groove plate, crudely drawn below, which is welded to the brake pedal. Yes, we obviously have somewhat different designs, but I don't think that it explains why my ratchet is well-worn and has failed before 550 hours and yours looks new with 3 times more use. Can anyone think of any other explanation, other than your ratchet was hardened and mine was not? I think with pictures from your TC45 and mine, it would be good to submit this to NH for an explanation. More feedback would be welcome, too. Thanks

 

[Charles Billings]

Below are two pictures showing the engagement parts for my 2006 TC45 parking brake. The tractor has 560 hours. The ratchet pawl shows worn and rounded teeth, the reason that it will not hold in the V-groove that is attached to the brake pedal. The question is why this part should have worn so badly and so relatively soon (problems with premature release occured with less than 200 hours) when Jinman reports no wear with three times the number of hours. It would seem that his part must have been hardened, whereas mine was not. Note that the V-groove looks a little rusty, but I don't think it has worn. If this is not the difference, does anyone have a better answer. Others have reported similar problems.

 

[jinman]

Charles, my apologies for being tardy at getting photos. I've been busy building a retainer wall and keep forgetting to get my pictures. I'm astounded at your pictures because I don't think I have that V-groove at all. It rained here last night and I can't work on the retainer, so maybe I'll get my ol' brain in gear and get those photos today.