Improved Brakes?

[soenke]

Hey,
if you have to do a lot of "down hill braking" ever thought about an exhaust brake?
its on my to do list:
http://www.gearingdynamics.com/exhaustbrake.htm

 

[ntsqd]

Am I getting this right? 4Runner front brakes are bigger than FJ60 front brakes? What about FJ62 front calipers?

My rear brakes are good and adjusted correctly. For starters I'll replace the front pads with better quality pads.

The casting looks slightly different, but isn't much different on physical size. You'll need to very lightly clearance the dust shields at the very outer edges for them to fit. Not a big deal, takes a minute or two with a small grinder.

What is different is that the 60/62 caliper has staggered bores (leading pistons are smaller than the trailing pistons - has to do with taper wear of the pads). The V6 caliper has all 4 of the same size pistons in it, and they are the same or roughly the same size as the larger of the 60/62 pistons.
I haven't actually calculated it, but I'd guess that it is about a 8%-10% gain in piston area.

I'm running them on my 60 using the stock master. Or at least I haven't changed the master, I've also not checked what bore size it is. I like the pedal, but pedal feel is a highly subjective thing.

 

[dieselcruiserhead]

The best thing I did (which is awesome/perfect for a Cummins application) is installed a hydrobooster and brake master cylinder from a GMC Safari or Chevy Astro van into my Cruiser. It is a fairly easy install, you use the juice from your powersteering pump that goes to the booster first and then to your power steering box. It smooths out both the steering as well as providing incredibly powerful brakes. I ran 60 series axles (well mini truck rear but same braking system) under my FJ55 so same application. No proportioning valve. All 4 wheels stopped excellently and even on 35's I swear the braking was better than all of the 4-Wheel-Disk European cars I've owned in the last 5 years (Saab, Volvo, Mercedes Diesel, Late Model VW Passat, etc).

 

[esh]

I noticed a difference descending long, slow, gravel roads. My OE FJ62 setup would heat up faster, sometimes requiring a stop to let them cool. Running the FJ80 master and ~90 4runner calipers now. Look for calipers with the heat sink like fins.

I am not sure that the larger bore master is a requirement, but with the new one it's one less thing to worry about.

 

[ntsqd]

Going to HydroBoost is a different kettle of fish. The considerable increase in booster power means that you can use a m/c with a large bore (for a small pedal travel distance) and still generate the necessary line pressures at reasonable pedal effort. A vacuum booster simply can't match the HB's performance.

The thing to keep in mind is that as good as an HB system can be, it won't over-come brake fade. If you are fading the brakes you are getting the pads, calipers, and most importantly the fluid hot enough to boil. If you can't drive slower, the only cure there is more airflow thru the rotor. I'd suggest the 62 dust shields as a starting place. You want to encourage air to flow into the center of the rotor at the wheel bearings (help keep them cool too) - not to either or both outer surfaces.
If you have boiled the fluid it is time to flush the system.

If a slotted rotor appears to help with the 'fading' then what is really happening is that the pads are over-heating and generating a gas between they and the surface of the rotor. With modern pad compounds this has become less common, but it is still possible. The slots provide a route for the gas to escape. Holes would too, but don't go there if rotor life span is important to you.

 

[mrlocksmith]

You might try some DBA slotted rotors on the front discs with some aggresive ceramic pads from Man A Fre. I have them on my '60 and they work well with my now 5900LB expo rig.

Mark


Linky

http://www.man-a-fre.com/feature_items/DiscBrakesAustraliaLonglifeSlottedBrakeRotors.htm

 

[dieselcruiserhead]

Boy ntsqd you know your stuff particularly about the difference between 60 and 62 rotor covers

Going to HydroBoost is a different kettle of fish. The considerable increase in booster power means that you can use a m/c with a large bore (for a small pedal travel distance) and still generate the necessary line pressures at reasonable pedal effort. A vacuum booster simply can't match the HB's performance.

The thing to keep in mind is that as good as an HB system can be, it won't over-come brake fade. If you are fading the brakes you are getting the pads, calipers, and most importantly the fluid hot enough to boil. If you can't drive slower, the only cure there is more airflow thru the rotor. I'd suggest the 62 dust shields as a starting place. You want to encourage air to flow into the center of the rotor at the wheel bearings (help keep them cool too) - not to either or both outer surfaces.
If you have boiled the fluid it is time to flush the system.

If a slotted rotor appears to help with the 'fading' then what is really happening is that the pads are over-heating and generating a gas between they and the surface of the rotor. With modern pad compounds this has become less common, but it is still possible. The slots provide a route for the gas to escape. Holes would too, but don't go there if rotor life span is important to you.

 

[bjowett]

That's right, 62 shields have that nice composite scoop...

 

[cruiseroutfit]

FWIW.

The 89'-95' 4Runner caliper as 4 - 40mm pistons versus the 2 - 35mm & 2 - 28mm pistons of the 40/60 Caliper.

Side by Side

You will need to trim ~1/4" off of the dust sheild on either side.

 

[ntsqd]

Boy ntsqd you know your stuff particularly about the difference between 60 and 62 rotor covers

I worked for wilwood in their R&D dept as a design engineer for 2 years, but the 60 vs. 62 dust shield education was recently courtesy of 'Mud.

Which reminds me, anyone got a set of 62 shields that they want to part with? How about just a picture of them?

As Kurt has shown though, my memory of the exact differences in piston sizes between the 40/60 and 4rnnr calipers was a bit flawed.

 

[dieselcruiserhead]

Not the best photo but here is a '62 axle I have lying around from when I picked it up/degreased. I always like the scoops and thought it was neat Toyota introduced them as well as the rear load sensor (as much of a PITA as it is)...

I ran a Wilwood brake master high volume as a clutch master on my last project -- worked great! Neat

 

[ntsqd]

Thanks Andre! I think I know what one of my next subtle mods is going to be......

 

[dieselcruiserhead]

No problem! When I get a chance I'll get some better pics. That axle also looks a lot better now as well...

 

[cumminscruiser]

Improved Brakes

I do have a hydroboost but I'm not ready just yet to install it, I do like the 4 runner calipers, I'm guessing they bolt up? That with hydroboost and better roters sounds like the ticket.