Manco Dingo Mechanical Brake Issue

[SquidBonez]

For whatever reason, the brakes on my Dingo are incredibly weak. They do slow you down, but they're so weak to the point where it's just dangerous. They cannot lock the rear tires at ANY speed - even when going from 3 mph. Both the rotor and the caliper is brand new. They seem to be adjusted as well as I can get them without always being slightly engaged. I hand-tightened the adjustment bolt until I felt resistance, then backed off a 1/4 turn and set the lock nut. I think the issue is that the brake linkage bar that came with the Dingo is too short, and doesn't allow the arm on the caliper to get it's full throw (the arm is already at 1/4 throw when NOT on the brakes), but it wasn't an issue before and I was still able to lock up the rear tires. Any advice?

 

[Karttekk]

How were they before you did the swap? Why did you replace them? You can change which hole the brake rod goes into at the pedal. I wouldn't back off the caliper bolt a quarter turn, tighten the adjustment bolt until there is a slight drag on the rotor then tighten the locknut.

 

[SquidBonez]

They were working fine up until the point I bent the rotor and had to remove the axle. Ever since I put the axle back on with the new caliper/rotor I've been having issues. The brake rod is connected to the middle hole in the pedal. I don't think I can change where it is connected because of how the spring is designed to connect to the pedal. You may be able to see what I mean by looking at this video I took for a previous thread of mine:
https://www.youtube.com/watch?v=j3PYQtfFLXI
On the caliper side, it is connected on the 2nd hole on the caliper arm (the one farthest from the caliper). As for the adjustment, I originally would set the lock nut as soon as I felt tension but then the brakes would seem to drag too much.

That being said, I never changed/detached the linkage bar from the pedal since I got the kart. It's always been connected to the middle hole.

 

[Karttekk]

Adjust the caliper bolt until the brake pad touches the rotor then tighten the locknut. There shouldn't be any tension or pressure on the rotor. Those brake systems are pretty tired, they need all the help they can get. Take that extra spring off of the pedal the move the rod to the bottom hole in the pedal. That will give you the least travel from the pedal to the caliper. That extra spring isn't factory as far as I know. Refer to the picture and adjust accordingly. If you had decent brake functionality before you did the swap you've got something out of whack. If the system is working properly no additional return springs should be necessary. I've sold a few karts with that setup that never had additional return springs. Make sure the rod isn't binding at the caliper, everything should move freely.

 

[Karttekk]

That picture was taken from an earlier DIY post.

---------- Post added at 10:59 AM ---------- Previous post was at 10:57 AM ----------

Are you able to move the rod to the other caliper lever hole just to see if that helps?

 

[SquidBonez]

Huh. Thought that secondary spring was stock. I'll do what you suggested and get back to you if it works or not. Nothing is binding at all, made sure of that. Thanks Karttekk.

That picture was taken from an earlier DIY post.

---------- Post added at 10:59 AM ---------- Previous post was at 10:57 AM ----------

Are you able to move the rod to the other caliper lever hole just to see if that helps?

I can, and I have tried, but it didn't seem to help.

 

[Bansil]

Did you get oil on the pad while rebuilding cart?

Have you tried to flat sand the pad on say 80 grit paper to get the surface clean, also on the disc is it too smooth?

Sounds like you need to bed the pad to the disk, scuff them both up and clean, then get to speed and apply even pressure to stop, let them cool and do it again

(no idea if the above works on gokarts, but it works on other things with disc brakes

 

[SquidBonez]

Just a quick update, haven't gotten a chance to drive it yet but I've removed the secondary spring and I found that it was actually part of the reason the pedal wasn't returning fully originally. Brake pedal is much better now and returns fully. Doesn't look like I will be able to change the hole I connect the linkage to on the pedal because the pedal spring blocks the lowest hole. Shouldn't be an issue since it worked before without changing the hole. I'll have to take it out to really dial in the brakes. I'll update again once I do.

 

[Karttekk]

Sounds like you got it. If everything is dialed in correctly the rod should only take a little bit of effort to plug it in the right hole. The pedal should travel freely, the caliper lever should move freely and there should be just enough free play in the pedal so the pads aren't dragging.

 

[SquidBonez]

UPDATE: brakes are still just as bad as they were before. If I tighten the caliper to the point where it is capable of locking the rear tires, the brakes will drag after I push the pedal down (yes, even after the pedal returns). If adjust it to the point where the brakes no longer drag, they aren't strong enough to lock up the tires at ANY speed - and then it's just dangerous again. I'm at my wits end with these brakes. You would think it wouldn't be this difficult...all I know is, whatever my next project turns out to be, its going to have HYDRAULIC brakes.

 

[Karttekk]

"They were working fine up until the point I bent the rotor and had to remove the axle. Ever since I put the axle back on with the new caliper/rotor I've been having issues."

Something happened from when you bent the rotor to when you replaced parts. Only you can figure it out. Take it all apart again and slowly reassemble checking how it's working after each step. No need to go hydraulic, step back and think it through. You'll get it.

 

[SquidBonez]

I've dissembled and reassembled the axle no less than 6 times. I took pictures of the setup before I took it apart the first time - everything is the same (I deleted the pictures after I reassembled it the first time, thinking I wouldn't need them anymore...stupid me). I know for a fact the issue is with the caliper somehow - I now have full throw on the caliper arm (I didn't before) but the brakes still drag after I depress them unless I loosen them to the point where they just barely work. And yeah, I have no intentions of going hydraulic on this little Dingo. I'd rather have crappy brakes than dump any more money into this thing. That would be for a future ground-up build project that I intend to keep for the long term. This project was to just have something fun and to learn the basics - I plan on selling it eventually.

 

[Brianator]

It's painful for me to see a fella suffering especially when he's put so much time and effort into trying to solve a problem... you want your brakes to work well and I don't blame you! Are you willing to post a few pics of the setup? I can't help but feel that SOMETHING is binding by your descriptions. Have you tested each individual component on its own for proper and smooth operation? Have you tried cracking all hardware free (from pedal to caliper mounting) so there's a little play everywhere to see if there's an improvement? Maybe it's possible to add another return spring on the caliper itself to ensure it opens back up all the way? Maybe the pads themselves are the issue, QC isn't great these days even in automotive and I've had to file/grind brake backing plates more times than I care to count just so the pads move freely within the caliper bracket the way they're supposed to! Ridiculous it is! I know I'm fishing but I'd like to try and help, I've been following this thread silently from the start...

 

[SquidBonez]

I'll grab some pictures when I can and update the thread when I get them. I'll get pictures from the pedal all the way down to the caliper. I made sure everything works individually, and that nothing is over-tightened. Everything has enough play to allow for fluid movement, all pivot points have been greased and greased again. I originally had everything so tight it would bind (as seen in the video) but after loosening all pivot points the pedal returns fully. The caliper also opens all the way - I made sure to check if the arm was returning fully. I think it's gotta be something with the caliper itself.

I'll get back to you when I can. But I do appreciate your interest in my thread. As frustrating as it is I am determined to fix it - purely out of principle! lol

 

[Brianator]

Sounds like you've covered all the bases so I'd tend to agree something is up with the new caliper... maybe pics aren't necessarily needed (well maybe a couple of the caliper itself, one showing the alignment of the pads and rotor). If you still have the old caliper and if it's compatible with the new rotor that would be something to try! How does your caliper operate exactly? Just one pad pushes out and over and the other pad is stationary is that correct? Also the adjustment bolt, what is it adjusting? Forgive my ignorance as I'm new to karting and don't even have one (yet, building my first one slowly) but I'm extremely mechanically inclined and can fix/upgrade just about anything I can get my hands on. Don't give up! You're hung up atm (pun intended) but you're close to the solution!

 

[mckutzy]

Over the years I have alot of problems with the mechanical caliper setups.. most happens to be from alignment, caliper ability to move (float), and lubrication..

Brian...
Some caliper have a take up bolt with a jamb nut. The actuator arm acts against this and the piston which pushes the pad to clamp. With the caliper floating, it stops..

OP- Is the caliper bracket and the caliper internals greased good?..

 

[SquidBonez]

Sounds like you've covered all the bases so I'd tend to agree something is up with the new caliper... maybe pics aren't necessarily needed (well maybe a couple of the caliper itself, one showing the alignment of the pads and rotor). If you still have the old caliper and if it's compatible with the new rotor that would be something to try! How does your caliper operate exactly? Just one pad pushes out and over and the other pad is stationary is that correct? Also the adjustment bolt, what is it adjusting? Forgive my ignorance as I'm new to karting and don't even have one (yet, building my first one slowly) but I'm extremely mechanically inclined and can fix/upgrade just about anything I can get my hands on. Don't give up! You're hung up atm (pun intended) but you're close to the solution!

Can't use the old caliper because A: the pads are almost completely worn down at an uneven angle due to the old rotor being warped and B: the adjustment bolt hole was stripped out. The new pads line up perfectly with the rotor. And yes, the one pad is stationary and held to the inside of the caliper with adhesive, while the other is pressed against the rotor when the arm is pulled forward. I'm thinking the new rotor I put on is moved over too far (its position can be moved, unlike the old rotor which was welded to the axle) and might be constantly rubbing on one side of the caliper, causing the brakes to drag. Not sure if that makes sense since the caliper sort of just "floats" on the rotor and it should adjust for that but...I've got no other ideas. Worth a shot.

Over the years I have alot of problems with the mechanical caliper setups.. most happens to be from alignment, caliper ability to move (float), and lubrication..

OP- Is the caliper bracket and the caliper internals greased good?..

Yeah, I can see why! These things suck. I was told they're easier than hydraulic...after working with them, I have my doubts. At least hydraulic calipers don't need constant adjustment, don't need to be in direct shot of the brake pedal, and are much more effective than mechanical calipers. I'm willing to bleed the brakes occasionally than deal with this nonsense...aaanyway...now that you mention it, I did forget to grease the caliper bracket and the caliper arm. I only greased the pivot points. That, paired with playing with the rotor's position a bit may fix my issues. We'll see when I work on it again.

As always, I will update this thread with any results. Thanks to everyone for the suggestions so far!

 

[Brianator]

Thanks for the explanation Mckutzy, sounds like it's as I imagined it.

It sounds to me like the float is for the initial alignment for the rotor and to get the pad that moves when actuated over to the rotor then you adjust the stationary pad into the rotor so it just barely drags. If the actuated pad is pushing everything over and not pinching anything that could very well explain what's going wrong for you. I could be wrong, I'm just trying to envision it by mentally referencing other brake setups from various things I've owned and worked on that are similar. Keep us updated!

*sorry if you read that before I edited it*

 

[mckutzy]

Grease the ways of the caliper where the bracket fits.
Grease the actuator pivot and piston groove/piston head that it fits.
Also the piston where it fits into the hole of the moving side.

I have done so much as to make sure the bracket has a smooth finish and no machine cut, bend marks or scratches to make a smooth ride through. Also the caliper groove is flat and no misaligned halves..

I did this for my buddy's bike, that has this setup and it locks up the rear end no prob...
Now with that being said... ya they still can be a pain in the rear...But.. when you can find that spot.. they work well...

 

[SquidBonez]

My thoughts exactly, Brianator. I'm thinking the rotor is not actually being pinched fully between the two pads. I think the actuating pad is just trying to do most if not all the work. I HOPE this is the issue because it's very easy to fix. We'll see. I'll also grease it up like mckutzy suggested.