Brake caliper/rotor info needed (was: disc brake conversion for FF rear)

[theferg]

Well my brakes are pretty sucky and I'm wantin' to go through the whole system and I'm wanting to convert to rear disc while I'm at it...only deal is I run a factory full float and I want to keep the park brake. I've been readin' the LCML archives for two days trying to find info but haven't found much regarding a disc brake setup for a rear FF that includes a park brake. Fabled stories and ideas of what to do, but can't find info where someones actually done it. No I don't want to use the t-case brake and I would prefer to use Toyota parts if possible. Anybody some real good info? Spill it.

-Ferg-

 

[beanz2]

Rear disc brake conversion for FF rear end--with a park brake

I've never done it, though I've thought about using the pre-82 Supra rear calipers. These are intended for non-vented rotors and have forward facing parking brake levers. There is a guy on this board who is using them while doing a SF to FF axle housing conversion and it looks pretty sweet.

Front Range Offroad Fabrication has been using these calipers on their minitruck FF conversion kit too.

Dave

 

[theferg]

Rear disc brake conversion for FF rear end--with a park brake

If the stuff I've read is correct, there is a way to adapt Toy front rotors to the backside of the rear FF hub...just have to machine the center a bit and use wheel studs from the front...? So the supra calipers fit a Cruiser front rotor or mini truck front rotor or?

I'm thinkin' mini truck or LC front non-vented rotors and supra calipers with the park brake. Then I would just need to fab a bracket/mount for the caliper. What about brake master cylinder? Would my stock FJ60 one work well with a disc rear setup? Or would i need a proportioning valve? Or would a 4runner brake master work better or? I'm also going to switch my front calipers to the larger front calipers from the 4runner.

Are there any other toys that use a caliper with integrated park brake? What brakes to newer runners or tacomas or t100s or tundras run? Or any other good qulity caliper with integrated park brake? I don't think I wanna use the cadilac caliper with built in park brake 'cause I didn't read too good of reviews in all the LCML archives.

Any suggestions?

-Ferg-

 

[beanz2]

Rear disc brake conversion for FF rear end--with a park brake

The back (inner) side of the FF hub has a somewhat rounded corner that needs to be machined to accept a rotor. The rotor can be machined to fit too OTOH. The 75 and 80 series factory rear disk rotors fit from the outboard side of the hubs but the inner diameter of the "hat" portion is larger. These are vented so they won't work with the Supra caliper. The Supra rear caliper takes a non-vented rotor only.

The newer Toyotas seem to use the minature drum parking brake inside the rotor design, so most don't have a parking brake built into the caliper.

For non Toyota rear calipers, I've seen newer Explorers and late-80's Troopers with built in parking brakes. They were both use vented rotors IIRC. The Trooper seems to have the correct Japanese metric fittings.

For a 4 wheel disk brake system, use one from a 4WDB car or truck. I'd suggest an 82-86 (15/16" bore) or 87-90 (1" bore) Supra master. You can use the stock one or minitruck if you can get the residual pressure valve out from the rear circuit.

For a proportioning valve, try it first (with the usual amount of load in the bed) on loose gravel or mud after you've done the rear disk swap. If your rear brakes lock up first, you need a proportioning valve to cut the pressure to the rear brakes.

Dave

 

[theferg]

Rear disc brake conversion for FF rear end--with a park brake

Thanks dave! Looks like I'm gonna try for one of those 4WDB masters you suggested, LC or Mini non-vented rotors, and loaded supra calipers with integrated park brake and figure something out for a caliper mount.

Just so happens that a thread about FF rear disc conversion popped up on PBB today as well. Looks like a guy from Oz has done LC front rotors and calipers on his FJ60 FF rear and has a little write-up with pics over there. Thought I'd link it up here in case anybody ever wanted this info.

Full Float Rear Disc Brake conversion

-Ferg-

(Full float fully floating disc disk FF convert conversion rear)

 

[cruzer]

Rear disc brake conversion for FF rear end--with a park brake

Was a write up on PBB in the j$$p section about using late 80s nissan 300z calipers with solid rotors that had an intigrated parking brake..probably similar to supra calipers..maybe easier to find...

Stew

 

[theferg]

Rear disc brake conversion for FF rear end--with a park brake

Cool. Thanks for the heads up I'll check them out.

I don't know much about brakes so I have a few questions... If you get such-and-such caliper, do you need to use the rotor it came with? Or just one that is the same thickness? Or just one that can cover equal or greaterthan surface area of the pads? Or both or? I'm just lookin' at all these calipers and tryin' to figure out exactly what I might want to use. I'm thinking just my LC rotors moved to the rear...but how do I know if a certain caliper will work with it or not? Obviously if the caliper can't fit over the rotor cause it's too thick, you have a problem, but how much "room" do you want in between the uncompressed caliper with pads and the surface of the rotor? Is that where a proportioning valve might come in handy?

I was tryin' to play it cool before with people talking about such-and-such caliper being for a non-vented rotor... What would the difference be? Will a vented rotor destroy a caliper that is not meant to be used with a vented rotor? Or destroy the pads too quickly? or?

How do you know where to mount the caliper? Is there a right-side up and an upside-down of a caliper? I know there is right and left side calipers... More specifally, if a caliper came on some axle mounted towards the front...would it harm it to be mounted on the backside (like rotating it ~90° around the rotor)?

Any idea how to tell if a caliper with an integrated park brake might work with my stock LC park brake cables (without actually examining the vehicle it came from)? How do you know if the park brake is forward or rear facing? If it's forward facing and you want rear facing, could you just switch sides of the axle (like move the right to the left and left to the right)? Or are they specific to rotation of the rotor (obviously they work when the vehicle is in reverse, but that is usually a much lower speed than in forward driving...)?

Here's a caliper from a 1990 Isuzu Trooper. Seems to have a park brake attachment on it...
1990 Isuzu Trooper (if it asks a zip code try your own or put in 84335)

And here's the supra caliper. I can't see on it where the park brake would mount (maybe it's not the correct picture...?)
1980 Toyota Supra

The caliper from the supra looks pretty small and only has one piston so I'm a little sketchy about it. I guess if people are already doin' it. I just want a conversion to be worth my money.

 

[beanz2]

I'd say as long as the rotor can spin without the brake pads dragging it's OK. OTOH the minimum thickness of the rotor should be important too so the caliper pistons don't fall out of the bore. A good guide would be the rotor minimum thickness of the original application. While the min. thickness is there mainly for heat dissipation and warping resistance of the rotor, it is probably safer not to go below this minimum on the rotor you end up using.

Non-vented calipers are often physically too thin to accept a vented rotor, that is all.

You mount the caliper so that the bleeder sits highest. Otherwise you'd have a heck of a time bleeding the brakes. This often dictates where you mount the caliper WRT the axle, but of course you can switch it side to side.

Switching side to side also messes up the direction your parking brake levers point. Most are made to point forward.

The 79-81 Supra calipers have a parking brake lever IIRC. These are becoming plenty in the junkyards. Go and check it out for yourself. Look for the ones like in the pic. You can ask FROR if they'll sell you the parts or make it yourself.