I want to mount brakes on the rear axle

[700 efi guy]

so I want to mount brakes on the rear axle. I'm running a 3 link semi independant type system. I was going to mount the brake caliper on the piece I'm mounting the pillow block on but that wont work because the pillow block articulates. I was then thinking about putting the rear axle in a tube, but I'm not sure how to mount the tube with out limiting the articulation. plus if the axle's in a tube I won't be able to mount the rear sprocket. am I going to have to run a band brake on the clutch?

 

[GreyhoundOfYerfDogs]

The pictures aren't too clear, but I think I get the gist of it.

Honestly, I think the suspension is going to need a bit of rework, as the present design looks like it would be squirrelly, and will dogtrack on turns. With an articulating (roll axis) axle, the chain will never stay on. Plus, the front sprocket will have to be mounted at the front pivot point, unless you have a long-throw tensioner idler, and even then, chain tension will be all over the map.

For a semi-independent rear solid axle, you'll need a shaft drive, not a chain.

Also, you'll need a panhard (transverse) rod with pivots at both ends, to prevent dogtracking.

If you're determined to have a brake on an axle whose mounts articulate, one thing to consider would be a caliper bracket that bridges over the disc and rides on its own two axle bearings. Run a link to near the front pivot point so it doesn't torque (in tension not compression when braking forward) and run the brake line along that.

 

[700 efi guy]

the drive sprocket is already aligned with the front pivot point of the suspension.

I'm only planning on 3 or 4 inches of suspension travel at max so dog tracking shouldn't be an issue, especially because it's very narrow and I'll be leaning. that and the rear suspension will understeer which is a dynamically stable condition. actually a lot of cars are set up to have a slight understeer, it makes the steering feel "tight". I really don't think dogtracking will be much of an issue, but I guess if I did I wouldn't have built it that way. I don't mind trying something and if it doesn't work cutting it apart and rebuilding. it's part of the fun.

the right hand drag link is attached on both sides, i think this will eliminate the need for the panhard rod. my only concern is the left rear tire wondering around a bit but I think i can eliminate this by sleeving the axle from wheel to wheel. (with the sleeve butted up against the sprocket on either side)

it's pretty tight in there, I'm not sure if i'll fit another link in, the right drag link will be in the way. and a band brake wont be much good if the chain does fall off. I guess I better make sure the front brake is pretty good when I test this thing out.

 

[sideways]

Your chain wont take the twist, it'l just fall off or snap.

The only way to attach the calliper would be to make a bar that goes between the two arms(attached to each are with bushers obviously and have the calliper mounted on a pivot on that bar.

Either way, I would add that bar to keep it all in alignment.

Also, it's not semi independent, it's dependant that can articulate.

If your relying on the movement of the bearing in the pillow block for your articulation then you are going to have problems. In fact, I would call that EXTREMELY dangerous.

Keep on going with it though. I'l be interested to see how you go. If you don't have one, fit a roll bar and harness.

Thanks

Hayden

 

[700 efi guy]

you guys are starting to scare me a bit. when I get back out in the garage I'll have a good look and reconsider. I never thought about the chain twisting. I guess thats the nice thing about these forums. whats dangerous about the articulating pillow block? will they come apart? I was kind of hoping to avoid the ladder bar type set up but I guess I'm going to be using cheap shocks anyways. it's not like it's going to be a cadilac.

 

[sideways]

Using the pillow blocks and bearings for your articulation means the bearings are always moving inside the housings, metal on metal, it's going to wear both of them bloody quick, most likely wearing the pillow block because they are generally made of worse metal. With this wear the bearing may eventually pop out of the housing with obvious disastrous results. Also, the pillow blocks aren't designed to take loads from the bearings on an angle. You could crack the thinner areas of the pillow block over the bigger bumps. Do your pillow blocks have zerk fittings on them? If so that will help. I'd be worried if they didn't actually.

What are you using for bushings where the arms connect to the frame?

Thanks

Hayden

 

[sideways]

You're going to need a bloody good chain tensioner too.

Thanks

Hayden

EDIT: could you please post some more pictures of your set up?

 

[700 efi guy]

Using the pillow blocks and bearings for your articulation means the bearings are always moving inside the housings, metal on metal, it's going to wear both of them bloody quick, most likely wearing the pillow block because they are generally made of worse metal. With this wear the bearing may eventually pop out of the housing with obvious disastrous results. Also, the pillow blocks aren't designed to take loads from the bearings on an angle. You could crack the thinner areas of the pillow block over the bigger bumps. Do your pillow blocks have zerk fittings on them? If so that will help. I'd be worried if they didn't actually.

What are you using for bushings where the arms connect to the frame?

Thanks

Hayden

I have oil impregnated brass bushings, and yes there are grease zerks (I can't believe we live in a time where we can't say nipple anymore)

 

[700 efi guy]

I'll have to take some morre pictures later, I'm home with my daughter (2years old) and can't play in the garage for now

 

[700 efi guy]

hey what about a drive belt instead of a chain? I could probably find a spot for an idler

 

[Doc Sprocket]

A single, automotive-style belt likely won't put up with the torque.

If you want an articulating live axle, I really see only two options.
1)mount the engine so that it moves with the axle (some folks refer to this as a swingarm)

2)Shaft drive.