Rear Disc Brake Conversion, pros/cons (2 Viewers)

[Btchnfj]

I have a 79 FJ40. Should I spring for the Rear disc brake conversion kit from Man a fre? I have the stock front disk, with the rear drums now. The cruiser is mostly a pavement princesses, its been through a full frame off restore. Tell me whatcha all think.

 

[Racer65]

There is no reason to. Front disc and rear drums is a perfect setup for the Cruiser. It's how Toyota designed it. '79 is a sought after year. Keep it stock and refute the temptation to modify anything.

 

[sadam_husain]

rear discs wont make it stop any better the only advantages you'd get is less maintenance (don't need adjusting like drum brakes) and they work better when wet and in mud

 

[murf]

I feel that going rear disc on my 82 that I certainly do get better braking power. Somewhat close to the rear drum if just recently cleaned and perfectly adjusted. The problem is that never seems to last very long. Not to mention fading from heat or water.

I wasn't sure at the time but now would say Id do it again. I lost my parking brake but with my auto trans I never used it anyways.

My .02

 

[Downey]

There is no reason to. Front disc and rear drums is a perfect setup for the Cruiser. It's how Toyota designed it. '79 is a sought after year. Keep it stock and refute the temptation to modify anything.

The only three problems with this way of thinking is (1) all modern vehicles come with 4 way disc brakes, (2) the value of an FJ40 is NOT less because of brake upgrades, and (3) the vehicle becomes safer. Bchnfj, I'll be sending you a PM.

 

[Racer65]

Not disputing that there are ways to make the Cruiser more modern or better. I happen to think you don't drive a Cruiser because it's modern. Over the years a lot of Cruisers have been modded beyond recognition, with Icon being at the extreme end of the spectrum. With all the American parts on the Icon it only resembles a Cruiser, much like how a FJ Cruiser resembles a Cruiser. There is no question those vehicles offer better performance and more modern conveniences, but do not come close to matching the driving experience or characters of the original FJ40.
Coming back to the topic, the point is that the OEM front disk / rear drum set up is more than adequate for a Cruiser that has not been modded with a jacked up suspension and monster tires. If the Cruiser is currently stock, why turn it into a mishmash of parts from different places?

 

[Downey]

Racer 65, I tend to agree with you, but only when my first FJ40 was brand new, and everything operated as brand new.

 

[Curt]

New tacoma's still use drums in the back, if they work i would keep them.

 

[mcjb]

Racer has a reason to think that way. He has the best riding 40 ive been in and its completely stock. I have a modded 40 with 4 wheel discs and a late model stock 40 with drum and discs and the latter probably stops better than the 4 disc brake vehicle. Both are in good condition. Id be very hesitant to mod an unmodded fj40 if it works ok. If it is heavily modded, have at it.

 

[snaggletto]

My '76 rear wheel cylinders were blown and drums were worn and everything was rusty. You can do the rear disc conversion for the same or less $ then rebuilding the drums. The brakes are better, and much easier to maintain in top working order. Not to say drums are ineffective, just that it made more sense to do discs rather than investing in drums. I don't see any cons at all, only pros. The originality argument is valid, but only in terms of a prestigious auto auction in my opinion.

 

[SouthBostonFJ40]

What would you use for an e-brake if you switched to rear discs on a 79 + truck? Or did 79 still have a old style e-brake?

 

[redrock]

If you have a stock, restored 79 fj40, why spend $600plus to downgrade your braking system featuring "rebuilt" parts from government motors and adapters for a workaround solution to a problem that doesn't exist?

From a technical, engineering standpoint, the best set of brakes put on a 40 series (or even the 60series given that they used the same components as the 81+ fj40s) was the 1976 to 1980 front disc and dual cylinder, twin leading edge rear drums.

The fixed caliper, 4 piston setup in the front was an engineering feat that was equalled only on the racing circuit and supercars of the day. The unequal diameter pistons were even a smarter and more eloquent design than the later, "improved" (read cheaper) larger diameter 4runner type.

I digress--the point is the rear stock brakes. The dual rear cylinder, twin leading edge was a system designed by Lockheed in the 1930s for use on airplanes. It effectively doubles the stopping capability using the same sized package. You can argue swept area, heat transfer, brake fade, and kinetic energy absorption, but where is the upgrade by slapping on a crappy, single piston sliding caliper from gm? Furthermore, you would also have to deal with the braking imbalance problem you just created by having to plumb in an aftermarket proportioning valve.

I also had a 79fj40 (and I'm sorry I ever sold it) and I remember being impressed with its stopping ability and capability. Back in the day, Toyota allowed trailer weights of up to 6500lbs without trailer brakes. Not bad for a 4500lb vehicle.

The question then, is how is some cheap, mass-produced, retrofitted, and "modern" brake component that wasn't even designed for a fj40 necessarily better and safer?

My thought would be save your $600 and keep it original (as Jay Leno points out, "it's only original once"). Simple maintenance is the biggest problem I have seen with fj40 brakes. Brake fluid does need to be flushed, especially in high humidity areas, as its hygroscopic nature tends to be particularly detrimental to Aisin components. A little dab of anti-seize on the wheel cylinder threaded adjusting bolt and the shoes will work like they are supposed to. And lastly, making sure that the correct wheel cylinder is in the correct position does make the big rubber rollers work better.

Another thought...adding front brake calipers to the rear axle also de-engineers your stock tandem master cylinder, as that drum circuit was designed for different fluid pressure and volume requirements. Again, toss out the fixed, stock proportioning valve and plumb in an aftermarket valve with a twist knob and hope that it is adequate.

 

[Anvil]

I also had a 79fj40 (and I'm sorry I ever sold it) and I remember being impressed with its stopping ability and capability. Back in the day, Toyota allowed trailer weights of up to 6500lbs without trailer brakes. Not bad for a 4500lb vehicle.

Toyota also advertised 7 people could ride comfortably at 70 mph. Have you ever tried this?

I have a 74 40, and converted to disc's on the front, which made a significant difference. I then converted the rear... the two combined, REALLY made a difference! I now feel comfortable in city driving. I would do this conversion in a heartbeat!

Just my 2 cents!

 

[snaggletto]

I was not aware if the '79's had the transfer parking brake or not. If it means losing the functionality of the stock parking brake then I would keep the OE drums and parking brake functionality.

 

[1911]

What would you use for an e-brake if you switched to rear discs on a 79 + truck? Or did 79 still have a old style e-brake?

I was not aware if the '79's had the transfer parking brake or not. If it means losing the functionality of the stock parking brake then I would keep the OE drums and parking brake functionality.

'79 in the U.S.A. still had the transfer case parking brake.

 

[Racer65]

My '76 rear wheel cylinders were blown and drums were worn and everything was rusty. You can do the rear disc conversion for the same or less $ then rebuilding the drums. The brakes are better, and much easier to maintain in top working order. Not to say drums are ineffective, just that it made more sense to do discs rather than investing in drums. I don't see any cons at all, only pros. The originality argument is valid, but only in terms of a prestigious auto auction in my opinion.

As mentioned above rear disc conversion costs about $600 in parts. Brake drums are around $100 a piece from Toyota, and rear wheel cylinder kit is about $150. You can have a brand new original setup for hundreds less than doing a conversion.

For your year the e-brake is not in the drums. Toyota's rear drum set up is just about the simplest design there is. The rusted parts can be easily replaced with new in about 1-2 hours using simple hand tools. Once you get a fresh start, the parts will last you a good 10 years.

 

[antFJ]

Pros - i always stop, the same feel every time, never adjust anything, the prop valve lets me fine tune my vehicle based on its specific weight

my truck stops better than my wife's 2007 jeep compass that also has 4wdisc. The kits out there work and they work VERY well. (I got mine from MAF)

cons - none?

 

[Stumpalama]

Pro: if you break a rear semi-float axle, the disk brake keeps the wheel and axle from walking out of the housing.

I like my disk brake setup and it stops my 37's just fine.

If you choose to go disks, you are optimally setup since the e-brake is on the t-case.

 

[honk]

As mentioned above rear disc conversion costs about $600 in parts.

Well....no. I'm just under $300. thanks to RockAuto, Downey, and you (prop valve splurge) for everything needed to disc the rear brakes.

I do have the machine tool ability to mill the S-10 rotor centers to the needed diameters. Without that it looks to be about $60. more for rotors ready-to-go.

 

[JohnnyC]

Pros - i always stop, the same feel every time, never adjust anything, the prop valve lets me fine tune my vehicle based on its specific weight

my truck stops better than my wife's 2007 jeep compass that also has 4wdisc. The kits out there work and they work VERY well. (I got mine from MAF)

cons - none?

Pro: if you break a rear semi-float axle, the disk brake keeps the wheel and axle from walking out of the housing.

I like my disk brake setup and it stops my 37's just fine.

If you choose to go disks, you are optimally setup since the e-brake is on the t-case.

These reasons are great reasons...

My biggest reasons was not having to adjust the drums and solid braking ... Every time