My Senior design project - a "Swamp Thing" tracked vehicle clone

[aczlan]

If you want more braking pressure for the same braking input you need to do one of four things
1. Change the linkage to have a longer lever on the master cylinders
2. Switch to smaller bore master cylinders with a longer throw
3. Switch to larger bore brake calipers
4. Add a brake booster (either hydro boost or vaccum powered)

Aaron Z

 

[3Lfarms]

If you want more braking pressure for the same braking input you need to do one of four things
1. Change the linkage to have a longer lever on the master cylinders
2. Switch to smaller bore master cylinders with a longer throw
3. Switch to larger bore brake calipers
4. Add a brake booster (either hydro boost or vaccum powered)

Aaron Z

Am I correct in thinking each brake master cylinder is only working one caliper? If so, then most master cylinders are designed to operate two or four calipers at a time. A small bore master cylinder may give OP the braking he needs.

 

[Garauld]

The service brake master cylinder (MC) operates the two red calipers in the following image. I have two clutch MCs (seen at top of image) each of which operates one of the blue calipers. I plan to swap out the service MC to a smaller bore MC. The steering brakes will probably be more complicated as the bore on their MCs is now small at 5/8" dia.

 

[pmsmechanic]

Something to consider is that you are putting the power through a differential. If you had a set of clutches for each track and a solid differential it would be a lot easier. When you stop the rotation on one side of the differential the other side doubles in speed.

 

[Garauld]

Yes, that would be a smart installation. Wouldn't you still need brakes on the disengaged side?

 

[pmsmechanic]

Yes, that would be a smart installation. Wouldn't you still need brakes on the disengaged side?

Yes. That's how the older crawlers used to be set up. A hand lever to release the clutch and a foot pedal to apply the brakes. A separate system for each side.

Newer agricultural crawlers are set up differently with some sort of power dividing system for the tracks. It's very easy to travel in a smooth curve.

The older setup is a pain because as soon as you release the clutch to steer you have half the traction as power is cut to one track. The newer setup keeps power to both tracks as you are turning.

 

[Fallon]

Yes. That's how the older crawlers used to be set up. A hand lever to release the clutch and a foot pedal to apply the brakes. A separate system for each side.

Newer agricultural crawlers are set up differently with some sort of power dividing system for the tracks. It's very easy to travel in a smooth curve.

The older setup is a pain because as soon as you release the clutch to steer you have half the traction as power is cut to one track. The newer setup keeps power to both tracks as you are turning.

Notes on Tracked Vehilcle Steering has a good overview of the myriad of advanced (and complex) skid steering transmission designs to work around the limitations of the classic simple designs. Not super relevant for a DIY build, but cool if you are an engineering type nerd.

I think most newish dozers just use a HST on each side like skid steers or CTLs use. At least ones you can move by truck without disassembling them. No clue what big dozers or modern tanks use. The higher the HP, the more heat managment issues, especially in an enclosed tank hill. I'd be curious if the big tracked ag tractors use HST as they are all about efficiency. There are no 60+ HP HST wheeled tractors because of the 15% HP penalty over geared transmissions.

 

[pmsmechanic]

Differential Steering | Cat(R) D6R through D9R Dozer Steering System - YouTube

This video does a good job of explaining Cat's system. Unfortunately it's a bit sophisticated for Garauld's design.

 

[MossRoad]

Notes on Tracked Vehilcle Steering has a good overview of the myriad of advanced (and complex) skid steering transmission designs to work around the limitations of the classic simple designs. Not super relevant for a DIY build, but cool if you are an engineering type nerd.

I think most newish dozers just use a HST on each side like skid steers or CTLs use. At least ones you can move by truck without disassembling them. No clue what big dozers or modern tanks use. The higher the HP, the more heat managment issues, especially in an enclosed tank hill. I'd be curious if the big tracked ag tractors use HST as they are all about efficiency. There are no 60+ HP HST wheeled tractors because of the 15% HP penalty over geared transmissions.

Deere 4066 is 66hp.

 

[TMGT]

What brake pads did you use? You might just need to bed the brakes or look for a more aggressive pad compound.

The last manual brake vehicle I owned (87 S10) was pretty worthless at stopping until the first couple stops, once you had a little heat in the brakes it wasn't bad.
The quality of brake pads made a huge difference on that truck compared to one with power brakes.