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Old 04-25-2011, 01:53 PM
ianacole ianacole is offline
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Default '84 Mini Truck Brake Upgrade

Greetings all! I'm looking to upgrade the stock brakes on the '84 Mini Truck axle in my FJ. I've reviewed a bunch of different threads on Mud and the interwebs, and have some questions hopefully someone smarter than I can answer. Here's the thread I'm using for reference: http://forum.ih8mud.com/79-95-toyota...-easy-pie.html

Questions:

In the thread it lists these parts as being needed:
Front calipers off 89 4runner with 22re
89 4runner 22re pads
1984 FJ60 rotors
Bearing Seals
Bearing Grease

Are these the right seals? http://shop.advanceautoparts.com/web..._228382889____

Anything else I should consider as part of this upgrade since I'll be pulling the hub and brake assemblies?

Thanks!

Ian
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Old 04-25-2011, 02:39 PM
leiniesred leiniesred is offline
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I have a 1985 mini truck front axle with the (original) S12W calipers from my 1989 V6 4runner and a pair of napa 1984 FJ60 vented rotors...But there is one more part on mine too. I have a spacer between the top hat and the brake rotor to move the rotor INBOARD. My brakes bolt up to the same side of the ears this way. I do not have any dust shields on the knuckles. Just a spacer. I've had this setup for at least 6 years.
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Old 04-25-2011, 02:55 PM
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I have the S13WB calipers on my 60 with stock 85Fj60 Rotors. The rotors are thin for the calipers (20mm) but they work. Anybody know of a thicker rotor that fits the same applications?

Looking for a 25mm thick rotor.

Also, in your linked post Dave, it states that going to a bigger master will result in softer pedal feel, this is backwards... bigger masters make the pedal stiffer. Also, in the linked post you state that the later 80 series MC's have a residual pressure valve for the disks... it's the other way around.. drum masters have the residual pressure valve for the drums.

Using a MC without the residual pressure valve will result in a pedal that has more travel or has to be pumped to get the wheel cylinders in the drums back out to their operating position. If the MC that you got is for 4 wheel disks you have to buy a residual pressure valve from someplace like summit and plumb it inline with the rears.
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Old 04-25-2011, 03:02 PM
ianacole ianacole is offline
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Thanks for the responses. As you can surmise, I'm trying to get better braking for the FJ40 ('73). Currently it has the '84 axle up front with the stock '84 brake system, stock drums in the rear, and a GM MC.
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Old 04-25-2011, 03:49 PM
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Quote:
Also, in your linked post Dave, it states that going to a bigger master will result in softer pedal feel, this is backwards... bigger masters make the pedal stiffer.
Didn't in my case, when I put in a new 1-1/16" master from a 1994 4Runner my pedal got softer (it stopped but not break-your-nose strong and felt weird soft) with no other changes (stock S12W calipers, 10" drums, 1" booster, stainless hoses). Went back to the correct (used) 1" M/C and pedal feel returned. Shrug, maybe it's a booster mismatch or some other problem, like trapped air? Would not surprise me to find that my bucket of rust has other issues. I came *this* close to driving it off a cliff this weekend. I hate old crap, would be nice if we just had one f'n vehicle that I didn't have to work on. Turns out that my M/C seems to be failing /again/, so I may get to try this experiment another time. I will remove that statement from the post.
Quote:
Also, in the linked post you state that the later 80 series MC's have a residual pressure valve for the disks... it's the other way around.. drum masters have the residual pressure valve for the drums.

Using a MC without the residual pressure valve will result in a pedal that has more travel or has to be pumped to get the wheel cylinders in the drums back out to their operating position. If the MC that you got is for 4 wheel disks you have to buy a residual pressure valve from someplace like summit and plumb it inline with the rears.
OK. I was just parroting what Marlin told me that of the two main non-ABS 1" M/C options, the FJ80 part has two residual valves, the Hilux unit (which never got rear disc brakes) doesn't. The explanation was that disc calipers require more volume but less pressure and have no lining wear compensation, so using a M/C without residual valves would mean the pedal has to travel further before the pads meet the rotor, thus the need for two residual pressure valves. IOW, the FJ80 M/C was sorta universal in that it would work with drums or brakes (with maybe different pedal feels?), whereas the Hilux unit would need an external valve to run rear discs.
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Old 04-25-2011, 05:02 PM
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Quote:
Originally Posted by DaveInDenver View Post
Didn't in my case, when I put in a new 1-1/16" master from a 1994 4Runner my pedal got softer (it stopped but not break-your-nose strong and felt weird soft) with no other changes (stock S12W calipers, 11" drums, 1" booster, stainless hoses). Went back to the correct (used) 1" M/C and pedal feel returned. Shrug, maybe it's a booster mismatch or some other problem, like trapped air? Would not surprise me to find that my bucket of rust has other issues. I came *this* close to driving it off a cliff this weekend. I hate old crap, would be nice if we just had one f'n vehicle that I didn't have to work on. Turns out that my M/C seems to be failing /again/, so I may get to try this experiment another time. I will remove that statement from the post.
Weird... hydraulically (mechanically), the bigger MC has less advantage over the calipers, so it takes more pedal pressure and *should* result in harder pedal feel. a smaller MC would have to move farther to move the same volume and have more advantage thus creating a situation where the brakes might feel a big softer. I am actually switching to a bigger MC today from my stock 60 one so well see if it actually works that way in my case.

Quote:
Originally Posted by DaveInDenver View Post

OK. I was just parroting what Marlin told me that of the two main non-ABS 1" M/C options, the FJ80 part has two residual valves, the Hilux unit (which never got rear disc brakes) doesn't. The explanation was that disc calipers require more volume but less pressure and have no lining wear compensation, so using a M/C without residual valves would mean the pedal has to travel further before the pads meet the rotor, thus the need for two residual pressure valves. IOW, the FJ80 M/C was sorta universal in that it would work with drums or brakes (with maybe different pedal feels?), whereas the Hilux unit would need an external valve to run rear discs.
Interesting.. Well, I bet Marlin knows the correct thing here I was under the impression that the residual pressure valves were for the drum brakes and were only on drum brake MC's. I hope I get one in the T100MC I am putting in today!
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Old 04-25-2011, 07:38 PM
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the residual valve is for drum brakes. it's to keep some light hydraulic pressure on the wheel cylinders, they are found inside the master cylinder where the line hooks up.

the proportioning valve is external to the master cylinder and it's to adjust the amount of hydraulic pressure between the front and rear in a drum/disc setup
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Old 04-25-2011, 08:37 PM
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:-S

Marlin Crawler: Big Bore FJ80 Brake Master Cylinder
Quote:
This is a genuine Toyota 1990-97 FJ80 Land Cruiser Brake Master Cylinder. This fits all FJ80 Land Cruisers and also makes for a great replacement part for older Pickup's and 4Runners that have a smaller bore. Aside from the FJ80, it also fits 1979-1995 Pickups/4Runners. Features 1" piston and residual valves for both front and rear. Works with both drum and disc brakes. Bolt on installation. Includes reservoir. On 1979-1985 Trucks and 4Runners the smaller factory bore works fine with stock, solid front rotors and 8" rear drums. If you upgrade the rear to larger 1986 and up, 10" drums and/or upgrade the front to a vented style caliper you will want to install a 1" bore master cylinder like this one for additional volume.

Upgrading your brakes without changing the master cylinder results in excess brake pedal travel. If you have upgraded your brakes on a 1979 to 1985 truck and now you have to push the peddle nearly to the floor, this master cylinder will make the peddle feel like it should.

Please note: In the picture above, the left outlet port operates the front brakes, and the right outlet port operates the rear brakes. Just remember, the front port (furthest from the booster) works the front, and the rear port (closest to the booster) works the rear brakes.
Marlin Crawler: Big Bore V6 Hilux Brake Master Cylinder
Quote:
Replacement master cylinder for older Pickup's and 4Runners with a smaller master cylinder. Fits 1979-1995 Pickup/4Runner. Features 1" piston. Works with drum rear brakes. Bolt on installation. Includes reservoir. On 1979-1985 Trucks and 4Runners the smaller factory bore works fine with stock, solid front rotors and 8" rear drums. If you upgrade the rear to larger 1986 and up, 10" drums and/or upgrade the front to a vented style caliper you will want to install a 1" bore master cylinder like this one for additional volume.

Upgrading your brakes without changing the master cylinder results in excess brake pedal travel. If you have upgraded your brakes on a 1979 to 1985 truck and now you have to push the peddle nearly to the floor, this master cylinder will make the peddle feel like it should.

Please note: In the picture above, the left outlet port operates the front brakes, and the right outlet port operates the rear brakes. Just remember, the front port (furthest from the booster) works the front, and the rear port (closest to the booster) works the rear brakes.
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Old 04-25-2011, 08:47 PM
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http://www.thebrakeman.com/valvetechi

We may as well start with the residual valve, because it is the first one that should be determined whether or not it is needed. This valve does exactly as its name suggests. It keeps a pre-determined amount of residual pressure in the line after you remove your foot from the brake pedal. This aids in preventing excessive pedal travel as well as insuring consistent height to the pedal. In a drum brake, heavy return springs are present to pull the shoes away from the drums. When not in use, the shoes are pulled back until they rest on a centering pin, usually located at the 12:00, or top position, on the backing plate also holding the wheel cylinder. In order to avoid the excessive pedal travel to move enough fluid from the master to activate the shoes, a 10-12 pound residual valve is installed in the line. Sine the return springs are stronger than the 12 pound valve, the shoes are pulled away from the drum in spite of the resistance so no brake drag results

A disc brake system, however, cannot tolerate this kind of pressure, as it would cause the pad to rub the rotor even when your foot was off the brake pedal. 10-12 pounds of line pressure on a disc brake will cause detrimental drag and a tremendous decrease in pad life. Worse yet, if the vehicle is driven at a consistent speed, the temperature will climb, due to this drag. This will cause the pads, rotors and brake fluid to swell causing lockup. At that point, the only way the brake system will release is for everything to cool back down.
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Old 04-25-2011, 09:04 PM
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That makes sense Ige and is consistent with Marco. So is Marlin's description wrong? I'm just really confused. Also, what then is the purpose of ~2 lbs residual valves that are used on hot rod disc brakes?
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