JaysonR

It seems like when I let off the gas and let the truck coast, it sounds like gears are crunching inside, but it still rolls. When I have the truck in my hand, and I just push it slowly, with either only the front, rear, or all four on the ground, I still hear the same crunching, but eventually the truck won't roll anymore, as if the wheels lock or something.

Is that normal, don't remember that when I first brought it. I can only imagine its the diffs, and I do have aluminum cases on both ends. have

JaysonR

Oh, by the way, when I'm on the gas, there is no problems. WHen its coasting at high speeds, doesn't seem to be any problems either.

Turanden

I had the exact same problem last week. I checked all the outdrives, the cvds, the pins, and could not find a problem. So the next thing I did was remove the tranny and then try to roll the truck. Everything was smooth as butter. So I thought, damn, must tranny is the problem. So I turned the tranny outdrives and guess was, there was the crunching sound, but not from the tranny, it was coming from the brakes. I took the brakes off, cleaned them up good, put them back in, and everything was great. The night before I had been out in the sand a bit and you could tell it on the break pad (which arent really pads since they are steel). They looked fairly pitted, but when I put them back together everything was fine, and has been fine the last week. Try cleaning them and see if it works. I bet it does.

bentgear

It could be a diff gear, or a pin backing out of a dogbone hitting something or a set screw backing out of an outdrive cup. Guess you have already checked the simple things like a rock in the spur gear teeth.

Ed M.

jefx

I'm 95% sure it's your brakes. The steel on steels set-up is very noisy, especially when the truck is still fairly new (I'm guessing that your truck is still pretty new?).

The binding problem is caused by the rotors shifting on the drive cup so that they aren't parallel to each other. This causes the brakes to lock up without warning, and if left unresolved, it will start damaging your drivetrain. As the rotors start "wearing" as you drive the truck more, the edges of the rotors will round out, and the problem will lessen.

There are a couple things you can do to help the situation though.

1. You can remove the rotors and pads and sand them down untill they are nice and smooth. This will remove some of the burrs and help them to spin more freely.

2. You could also (although I've never tried it) set the pads up to where there are two pads on one side of the rotors and one pad on the other side, thereby shifting the center pad from being inbetween the rotors, to having it on one of the outsides. This will place the rotors right next to each other, removing the gap between them. It's mainly the gap that causes the problem.

3. Get the Losi HP pads. I don't know exactly why this resolves the issue, but it does.

4. Get an entire aftermarket brake setup.

JaysonR

Thanks everybody, dapicco too

So I hear its the brakes, outside of RCU also. I planned on buying the dynamite throttle linkage, and putting on the HP pads from Losi. Hopefully that will resolve it. We'll see

Yeah, the truck is newer in comparison to some of the other trucks out there. Still less than a year old, but I brought it over the winter time, so its just starting to get some real usage now. I've checked out everything else, rebuilt CVDs, cleaned and put new oil in my diffs (50,000 in front in back), and cleaned and oiled everything to the point it looks like its brand new. Still same noise. Only thing left is the brakes. Trying to wait for the dynamite linkage though. I read in another thread that its a huge difference between the old servo saver and Dynamites. Is that really true?

jefx

Ya, I meant "Newer" as in "not used much". The stock brakes will fade with more usage and will become more friendly, but it takes some time. The best and cheapest option is the HP pads, which work awesome. Seriously, the HP pads are one of the best investments you can make on the LST (value/cost). Just make sure to sand up the stock discs (so that they're very smooth) before using the HP pads, otherwise you'll chew up the new pads much quicker.

alvinm

Before you go buying stuff check and see if your brakes are dragging at idle.You may be able to dial out the brake drag which may be the cause of noise.Check the end points on the throttle.

bentgear

jefx, do you think taking a rubberized tip in a dremmel to the inside edge of the disks and the outside edge of the plates to break the sharp edge would help? I am at the point I need to do some replacements, disks groved and plates almost worn thru. May just go with new disks and the HD plates but still thinking about putting a slight radius on the inside edge.

I keep mine adjusted so that at full brake the tires don't lock up, but stop quickly. I guess with all the wear I have not noticed the problems you are describing.

Ed M.

JaysonR

My brakes are faded to the point that they don't stop like they used to. I've got about 3 gallons through the truck (3 different engines too), brakes are completely different from 2 months ago. Now they are slower to stop, still fading.

So, do I really have to take the transmission out to put the HP pads on? Is there another way?

Sgt. Canada

No, you don't have to take the tranny out to change the pads. I did it while it was in place. You have to take your reverse servo out, but it's not that big a deal. While it's much more straigforeward (and easier than you'd think) to take the tranny out, putting on the pads with th tranny in takes some practice, and overall it's more of a pain.

Nitronutt

My Feedback: (2)

The disks need x amount of space between them and the pads are what keep that space. Removing material (Other than dressing the edges) will usually accelerate wear or cause undesired results. It is possible to swap the 2 outside pads with each other to give them a fresh edge, but the center pad definately needs to be replaced. The 3 pads come in a kit with the retainer bracket for $3-$5 so, don't sweat the cost. I bought new rotors at the same time for another $3-$5 for the set of 2, so for less than $10 you can have an entire brake overhaul.

It is necessary to rebuild instead of trying to dial it out because the brakes stop running parallel to each other as the pads get worn and begin to point toward each other on one side (Causing the binding and noise). No amount of dial out will help...believe me...I've tried!

bentgear

Nitronutt; From jefx post it seems that new brake systems are the ones having the problem, thats the reason for my question about putting a slight radius on the inside hole of the new disks before installing them. My disk are grooved pretty bad and like I typed my plates, especially the center one are almost worn thru. With all this slack from your post I should be getting the problem in a major way, but I'm not. Also, I don't add any more free travel in my linkage than normal, I just reduce the total throw on the brake side so I don't go into uncontrolled lockup. Most of the time spent with mine is on the track racing so I like it to be very predictable.

Guess I will just do some replacing of parts and see what happens, or at least go ahead and get the parts to have ready when the plates finally get a hole in them.

Ed M.

Nitronutt

My Feedback: (2)

I am more addressing the issue of random brake binding rather than the noise issue.

I am saying to replace the pads and rotors completely...with either the stock pads OR the HP pads. I now see what you were aiming to do by using your dremmel (To aid the break-in of the new brakes, right?). I would get the new pads (Whichever ones) and rotors and dress the edges until smooth...like you said. I was thinking that you were going to file/polish the old pads and rotors down...which would increase your chances for binding.

Jefx is saying that the sound problem lessens as the parts break in. I agree. When the pads and disks get overworn, they seem to start binding (Or so is my experience). Like Turanden, my first thought was CVD's, then Diffs, etc. but what it came down to was the brakes. It seemed to happen when running slow and turning sharp (Hence why I first thought CVD's). If I was heavy on the throttle or traveling fast, the problem never seemed to show itself. I replaced the pads and rotors and the problem has been eliminated.

bentgear

Thats it. Never had the problem before, but if its something that is showing up it would be nice to knock it in the head before it becomes one. Every time I have run into something like that it has been a pin or set screw backed out of place. In fact til this post I have not had the brake assy. apart, never had the need.

Thanks guys,
Ed M.

JaysonR

BentGear, when you say a slight radius, I didn't know exactly what you meant, and I just wanted to clarify. Do you mean just a slight groove from the center of the disk to the outside edge, similar to the disk in this picture, but from edge to edge?
http://www.crazynutracing.com/produc...roducts_id=368

It seems like you are saying that as the pads and or the disk wear, that extra space from where there used to be material is the reason for all of noise and catching. Am I understanding that right? Asking because I didn't realize that much material wears off the pads and disks, I thought lack of wearing was the reason they decided to put a steel on steel brake system.

bentgear

Nope, what I took from jefx's post is the problem got better as a little wear developed in the center of the disk at the edges. I don't think I am doing a very good job of explaining my thoughts. Take the disk and lay it out flat on the table. On a new disk where the inside hole meets the face of the disk its 90 degrees.(square). What I interpreted jefx post to mean is that as you get a little wear on the square edge the problem will go away. I think the sharp edge of a new disk my be catching slightly on the drive cup not allowing it to shift positions as needed. By taking the right dremmel bit and just breaking the edge slightly a slight wear characteristic could be duplicated.

Make any better sense now?

Ed M.

jefx

Ya, that's pretty much what I was saying.......At least that's been my experience. As my stock brakes (LST #633) started wearing in, the noice reduced itself, and the random binding eliminated itself. After studying the brakes design, you'd figure that the discs would be forced to remain perpendicular to the drive cup because of the pads and such, but somehow they kept getting stuck cockeyed. The only thing I can attribute this to would be the sharp edges on the inside of the discs themselves. After some wear on those edges (and/or maybe the drive cup wearing in), the binding stopped itself.

Either way, after having some wear and replacing the stock pads with the HP pads, I've never had that problem since.

bentgear

Had to go to two hobby shops today, pads from one and disk from the other. No use to do the test tho, drive cup has some wear so any testing would be invalid. I did decide to try the HD pads.

Thanks for the info.

Ed M.

Nitronutt

My Feedback: (2)

Are the HD pads thicker?? Better separation and a more snug fit...as well as a revised design (However slight) might be what fixes the issue.

bentgear

Not sure Nitronutt, I will compare them tonight and get a thickness difference. They may well be because I was wondering if my brake linkage rod was going to be long enuff since I had to back off it so much!

Ed M.