Which Brake Booster?

[IBFJ62]

So I'm redoing the brake system on my '83 short bed, upgrading to V6 fronts and stock disc rears, and I purchased a T100 (advertised as fitting V6 early 4runners, pickups) double brake booster to go with the new 1" MC. Does not want to fit. The thread studs are much too short to fit through the firewall and have any standoff away from the firewall, which doesn't allow any room for the steering shaft. What booster have you guys used successfully? Thanks!

 

[gnob]

So I'm redoing the brake system on my '83 short bed, upgrading to V6 fronts and stock disc rears, and I purchased a T100 (advertised as fitting V6 early 4runners, pickups) double brake booster to go with the new 1" MC. Does not want to fit. The thread studs are much too short to fit through the firewall and have any standoff away from the firewall, which doesn't allow any room for the steering shaft. What booster have you guys used successfully? Thanks!

i thought something about the turbo trucks have something that works.
problem is the early trucks use that spacer where most everything else doesn't.

 

[IBFJ62]

It seems the spacer is to give the booster outward clearance from the firewall for the steering shaft to slide under it.

 

[ntsqd]

How thick is the spacer?

 

[IBFJ62]

 

[IBFJ62]

In my interweb searches it seems that if the larger V6 calipers are used with the stock booster and upgraded 1"MC, the brake pedal pressure sucks. I hoped to use the double booster to get good brake pedal feel, but the diameter of the later brake booster is significantly larger as well. If there was a double booster with longer studs it might work, but not sure what year/model would be compatible...

 

[ntsqd]

My advice is to use the 4rnnr V6 booster and m/c. I own one of those trucks and the brakes are the best Toyota brakes that I've ever driven. Light pedal, not terribly long stroke, and most importantly, good modulation. The only question is how to adapt the booster to the early truck. If the booster's studs are short enough it might work to use coupler nuts and some set screws to extend them.

I started this thread in the 60 forum some time ago when I was closer to working in designing brake components and assemblies: Comments on brakes - https://forum.ih8mud.com/threads/comments-on-brakes.256361/

 

[gnob]

i couldn't find anything concrete but here's more confusion for you.

dual brake booster for a 79-83 toyota

www.pirate4x4.com

 

[ntsqd]

I can say from experience that the V6 calipers and FJ vented rotors are a great upgrade, but that if you're looking for substantially better brakes that you need to move to a larger rotor diameter.

EDIT: A feature not often realized is that vacuum boosters have a response curve. Two boosters that appear identical can have dramatically different response curves. One will drive like a Sports Car while the other will drive like a 1976 Coupe deVille. Choose your booster donor carefully.

 

[bkg]

if space is an issue, may be worth looking at an iBooster as well.

 

[IBFJ62]

Does anyone have experience with the stock MC/Brake booster and the stock front discs and replacement rear discs? After chasing part #'s and ???'s, I've come back around to maybe just replacing the rear drums with discs, which I have already done, and keeping the stock front brake setup. I'm not running anything over 33's, and I don't recall the brakes being all that bad on the truck (although it's been 15+ years since she ran).. I'd like to upgrade the fronts to larger V6 discs, but not at the expense of a crappy pedal feel with a 1" MC, without the 2xbooster upgrade..

 

[ntsqd]

In today's driving I think that you're going to want the vented rotors. Do not have to do the V6 calipers to work with them, can use, I think, either the FJ60 calipers or the 4cyl 4rnnr calipers - both of which should have a total piston area roughly equal to, if not the same as, the existing calipers. Which translates to mean that the pedal will feel like you're used to it feeling.

FWIW I use Rock Auto for all of this sort of research. Finding out what the piston sizes of each caliper is will be fairly fast and simple. Will need to set up Excel to do the piston area calcs in the event of one or more of those calipers having two different piston sizes. Ah yes, the '80 4WD Mini caliper is differential bores and the '84 FJ60 are all the same size. So a calc is needed. Looks like I can't attach an Excel file or I could post one already doing this calculation.

 

[pappy]

In today's driving I think that you're going to want the vented rotors. Do not have to do the V6 calipers to work with them, can use, I think, either the FJ60 calipers or the 4cyl 4rnnr calipers - both of which should have a total piston area roughly equal to, if not the same as, the existing calipers. Which translates to mean that the pedal will feel like you're used to it feeling.

FWIW I use Rock Auto for all of this sort of research. Finding out what the piston sizes of each caliper is will be fairly fast and simple. Will need to set up Excel to do the piston area calcs in the event of one or more of those calipers having two different piston sizes. Ah yes, the '80 4WD Mini caliper is differential bores and the '84 FJ60 are all the same size. So a calc is needed. Looks like I can't attach an Excel file or I could post one already doing this calculation.

He is correct. IFS trucks had vented rotors, but didn't get the larger calipers until 1988 with the V6. Double check, but I believe 1986-1987 calipers are the same size as yours, but wider for the vented rotors.

 

[ntsqd]

Just had a look at RA because I'm curious. The '86 Mini 4WD caliper is the same p/n ("2C827" in Cardone's system anyway) as the '84 FJ60 caliper. It has Ø42.75mm pistons. The Cardone caliper p/n for an '83 4WD Mini is 19821 and it listed as having Ø42.7482mm pistons. That is too small of a difference to notice, assuming that the 2C827's pistons sizes aren't just rounded off.

 

[Txfireman]

This link was helpful when upgrading my '85.

Toyota 4x4 Brake Master Cylinder and Brake Booster Specs

Mushy brakes? Worn out brake master? Read here to find out about larger bores, dual diaphragm boosters, and better stopping for big tires on your Toyota.

www.roundforge.com

 

[ntsqd]

What rear discs did you use?

 

[pappy]

My only reluctance to rear disk conversions on our trucks is the parking brake. Ya, you can get a disk on the transfer case, but my experience is they don't hold. There has also been lots of noise about using Eldorado calipers, but I don't think I ever saw a functional install.

 

[IBFJ62]

These are the stock solid front rotor and caliper. I hear ya on the parking brake, I do plan on the transfer case caliper. Interesting to hear your feedback on that.

 

[ntsqd]

I suspect that is going to be too much rear brake at speed. You'll end up having to crank the proportioning valve way down. There is a 2 piston caliper used on the 2WD trucks, but it is only a ~5% reduction in piston area. Not enough to make trying to get them to fit worth doing it.

It is really hard to generate enough clamp force in a mechanical caliper unless an excessively long cable pull is allowable. A drum brake is actually better suited to a parking brake type of use.
Any of those Caddy hydro-mech calipers are a waste of time. Although borderline too big for the rear of these trucks the service brake function works like it should. I've never known anyone who could keep the p-brake function working for any period of time. That includes a pretty anal Mech Engineer who wrote an article on how to make them work, and then gave up and went with the Explorer rear discs because he was always having to twiddle them to keep the Cad calipers functioning correctly. The Explorer p-brake function is a drum inside the hat of the rotor. I know of no one offering these brakes for a Toyota and that's a crime.

 

[IBFJ62]

I was thinking of adding an in-line proportioning valve to adjust the pressure to the rear. Thoughts? Thanks