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RicardoJM
11-20-2011, 07:50 PM
I lost the rear circuit in my master cylinder and decided to make the switch to disc brakes in the rear of my FJ40. Drums had always been fine and never failed to stop my truck, but I was needing to replace the master which likely would have caused the cylinders to pop - well probably not but I put that in my rational for making the swap.

Disc brakes in the rear of an FJ40 is a really easy and straight forward project. You will need to source some brackets and bolts. There are several vendors that all offer these. I got a pair of brackets from a club member that had an extra set. A trip to Fastenal and I had the 3/8" 24 pitch X 1.25" bolts and accompanying lock washers and nuts.

http://www.risingsun4x4club.org/uploads/ricardojm/reardisc/w_reardisc001.jpg

The Advance Auto had rotors, calipers and pads in stock. Part numbers were

Rotors - YH141454
Calipers SLC160 and SLC161
Pads - MKD154


http://www.risingsun4x4club.org/uploads/ricardojm/reardisc/w_reardisc002.jpg

I took trip out to Redline and Justin machined out the center of the rotors so they would fit on the axle. Justin did a great job in opening these up to the perfect width. As he has axles on site, he did a test fit to insure they were correct. Here is what the rotors look like on the lathe and the measurements being checked.

http://www.risingsun4x4club.org/uploads/ricardojm/reardisc/w_reardisc016.jpg

http://www.risingsun4x4club.org/uploads/ricardojm/reardisc/w_reardisc015.jpg



TSM in Castle Rock has stainless steel brake lines that are designed to run from the t-block on the rear axle to the calipers, so I went ahead and picked them up. I also grabbed a 1" master out of a 91 T100 and had a proportioning valve from when I did the front disc brakes a couple of years ago. The hex wrench is a 3/4" and is needed for the caliper bolts.

http://www.risingsun4x4club.org/uploads/ricardojm/reardisc/w_reardisc003.jpg

This conversion is well documented and I'm not sure that I have any new insight, tips/tricks that have not been covered by others. That said, there were three significant time syncs in this project that made it go much longer than it should have for me.

The first was cutting out the drum backing plate. I had read that you could cut out the drum backing plate, which would allow you to install the disc brackets without having to remove the axles, i.e. no need to get into the diff. As I am going to be installing an ARB soon - I thought this would be the way to go. Well, after 30 minutes with the grinder, it became very appearent to me that I was not going to be able to cut off the backing plate - but I gave it another 1/2 hour before giving up on the idea. Fifteen minutes later (10 of those were waiting for the diff to drain:rolleyes:) both axles were out.

The second time sync was not really related directly to the conversion, but I figured that I would remove my lock rite and install the original spider gears. Seems easy enough and it really was after I spent what must have been a hour figuring out how to put the gears back in. I'm sure if you ever taken the balls out of a birf, you've had a similar type of experience. Getting it all back together is real easy, but you have to try all the ways it won't work before you stumble on the way that does work.

The third has time sync was that I had to rotate my t-block slightly to install the brake lines. Of all the issues, this is the one that I should have really seen the resolution quickly - but I didn't. You can see here, the slight rotation that was needed.

http://www.risingsun4x4club.org/uploads/ricardojm/reardisc/w_reardisc007.jpg

Oh well:D, overall I started about 9:00 am yesterday and had all the rear end buttoned up by 6:00 pm. Here are a few shots I snapped of the work.

http://www.risingsun4x4club.org/uploads/ricardojm/reardisc/w_reardisc008.jpg

http://www.risingsun4x4club.org/uploads/ricardojm/reardisc/w_reardisc009.jpg

http://www.risingsun4x4club.org/uploads/ricardojm/reardisc/w_reardisc010.jpg

http://www.risingsun4x4club.org/uploads/ricardojm/reardisc/w_reardisc011.jpg

This morning I installed the new master cylinder. Here you can see the push rod from the booster. Many times, people do not check the length of this rod and it causes their brakes to drag and lock up. If anything, I adjusted my rod too short but I am happy with the pedal feel.

http://www.risingsun4x4club.org/uploads/ricardojm/reardisc/w_reardisc004.jpg

The new master after being bench bled was installed and the brake lines hooked up.

http://www.risingsun4x4club.org/uploads/ricardojm/reardisc/w_reardisc006.jpg

The BoomBoom gave me a hand with bleeding the system and the new brakes work very well. They stop straight and will lock up if you get on them:thumb:. I did not want install the proportioning valve unless I had to. The rears do lock up first, so it looks like I will be putting in the valve, probably when I install the ARB in the rear. Oh, I definitely do not miss the noise and bump steer from my locker:D.

Here is the old master and drum internals.

http://www.risingsun4x4club.org/uploads/ricardojm/reardisc/w_reardisc005.jpg

kvanoort
11-20-2011, 08:36 PM
Great write up as usual!

nattybumppo
11-20-2011, 09:26 PM
Do you have an estimate of your costs? I'm just thinking how it compares to a complete kit from, say, Mananotsofree.

subzali
11-20-2011, 09:56 PM
kewl :D

Is that a disc brake master cylinder?

ttubb
11-20-2011, 10:34 PM
You are gonna love those rear discs, but you will need to use the proportioning valve. Nice write-up and great job! Terry

Dr. Schlegs
11-20-2011, 11:12 PM
The non-ABS 80 series has a proportioning valve built into it and is reported to eliminate the need for an external proportioning valve. You are going to love the discs, so simple to replace and easy to maintain.

RicardoJM
11-21-2011, 07:39 AM
Do you have an estimate of your costs? I'm just thinking how it compares to a complete kit from, say, Mananotsofree.
My costs on this project were pretty low. I have been doing a bunch of brake work on my rigs and with the coupon/discounts from Advance I got some great deals. Even without the discounts, the costs were reasonable. The kits are very convenient, but there is a premium value that comes along with that. In my case, my out of pocket dollars were less than a kit - but not by a huge margin when you consider the fuel costs and time spent running around.

I would definitely recommend TSM's brake stainless steel lines, they are very reasonably priced - even comes with the banjo bolts and copper washers. Redline's machining of the rotors was top notch as well and very reasonably priced.


kewl :D

Is that a disc brake master cylinder?
No. The master came out of a 93 T100 that had discs up front and drums in the rear. As Dr. Schlegs indicated, apparently you can get a master from a Toyota (most commonly mentioned is the later 80 series, but also mentioned are supras) that had discs all around and not need a proportioning valve. As this master came from the year that 4 wheel discs were available and I could not see any difference between the front and rear outlets - I figured it was time for some first hand experience on the subject. Of course all I can say with confidence is that in my case, I will be adding the proportioning valve. Don't get me wrong, even without the valve the truck stops great - much better than it did with a broken master cylinder - its just that I can definitely lock up the rears before the fronts.

subzali
11-21-2011, 08:06 AM
Sorry Ricardo, I meant the master cylinder you took off. Should have been more clear in my question.

RicardoJM
11-21-2011, 08:10 AM
Sorry Ricardo, I meant the master cylinder you took off. Should have been more clear in my question.

Oh, no it is not either. It definitely came off an FJ40 that was running drum brakes all around. It definitely needs to be rebuilt as the rear outlet is not working consistently. You are welcome to it, if you'd like it. :D

subzali
11-21-2011, 09:17 AM
I am good, I bought a new OEM one a few years ago and it's working great :thumb:

I was just wondering...

SteveH
11-21-2011, 09:51 AM
Nice writeup and photos - thanks!

nattybumppo
11-21-2011, 03:12 PM
So I'm wondering how they work compared to your front disk/rear drum set-up. Let's do a test. We'll drive side-by side down Broadway from Colfax at 60 mph and see who can stop when the protester steps out in front of traffic to make some point...I don't know what point...and who runs him over.

Romer
11-21-2011, 03:15 PM
Nice write-up!

L43dean
11-21-2011, 08:33 PM
So I'm wondering how they work compared to your front disk/rear drum set-up. Let's do a test. We'll drive side-by side down Broadway from Colfax at 60 mph and see who can stop when the protester steps out in front of traffic to make some point...I don't know what point...and who runs him over.

Don't quit your day job. On second thought... Have a nice day!

Air Randy
11-22-2011, 11:56 AM
So I'm wondering how they work compared to your front disk/rear drum set-up.

My .02:

The rear disc brakes and rear drum brakes, when both are properly maintained and adjusted will stop the rig equally under normal driving conditions.

However if the brakes get wet, or really hot, the discs will beat the drums hands down. And they will last longer with less maintenance.

nattybumppo
11-22-2011, 01:30 PM
Don't quit your day job. On second thought... Have a nice day!

:hill::hill::hill:good comeback!

Dr. Schlegs
11-22-2011, 08:11 PM
My .02:

The rear disc brakes and rear drum brakes, when both are properly maintained and adjusted will stop the rig equally under normal driving conditions.

However if the brakes get wet, or really hot, the discs will beat the drums hands down. And they will last longer with less maintenance.

Plus you have brake fade which is more prevalent in drum brakes. From my days of working in a garage, I was always told that the brake dust acted like marbels in the drum and effected the stopping power as well. Further,the heat from the drum causes brake shoes to break down prematurely.

Uncle Ben
11-22-2011, 09:09 PM
Huge bonus on a C-clip rear axle is if you break the axle the rotor is contained in the caliper so it wont walk out and you might be able to get to the side of the trail or even further!

Air Randy
11-23-2011, 10:17 PM
Huge bonus on a C-clip rear axle is if you break the axle the rotor is contained in the caliper so it wont walk out and you might be able to get to the side of the trail or even further!

True dat! I broke a rear axle on Poison Spider 3 years ago and was able to drive it about 3 miles back out to the trailer.

RLMS
11-26-2011, 10:56 PM
Ricardo, you and write ups, go hand and hand! Great job BTW!!!


Justin

Dr. Schlegs
11-27-2011, 08:03 AM
True dat!

When did you become Gangsta???

Uncle Ben
11-27-2011, 10:02 AM
When did you become Gangsta???

When he gave back the badge! ;) :hill:

Rezarf
11-27-2011, 01:49 PM
My .02:

The rear disc brakes and rear drum brakes, when both are properly maintained and adjusted will stop the rig equally under normal driving conditions.

However if the brakes get wet, or really hot, the discs will beat the drums hands down. And they will last longer with less maintenance.

I'd also throw out there on a really steep incline and needing to brake with a trailer, the disks will out perform the drums in keeping the rig from rolling back

Uncle Ben
11-27-2011, 01:55 PM
My .02:

The rear disc brakes and rear drum brakes, when both are properly maintained and adjusted will stop the rig equally under normal driving conditions.

However if the brakes get wet, or really hot, the discs will beat the drums hands down. And they will last longer with less maintenance.

Apples to oranges! True fact that when drums are properly adjusted they provide sufficient stopping power. The variance is that disc's do not need to be adjusted and will always have predictable and sufficient stopping power while the drums will decline after every stop until adjusted again.

Air Randy
11-27-2011, 11:19 PM
Apples to oranges! True fact that when drums are properly adjusted they provide sufficient stopping power. The variance is that disc's do not need to be adjusted and will always have predictable and sufficient stopping power while the drums will decline after every stop until adjusted again.

I think you and I are in violent agreement that disc brakes beat drum brakes hands down. I was just trying to prempt the hard core old school guys preaching about how well properly maintained and adjusted drum brakes work.:D

Air Randy
11-27-2011, 11:21 PM
When did you become Gangsta???

You don't have to be gangsta to talk gangsta, evidenced by the fact that 99% of all of the "gangstas" you see out there are wannabes.

Rzeppa
12-06-2011, 01:22 PM
Huge bonus on a C-clip rear axle is if you break the axle the rotor is contained in the caliper so it wont walk out and you might be able to get to the side of the trail or even further!

That's why it's called a "poor mans full floater".

I was leading Porcupine and had a guy break his rear axle on the ledges, we got him out with straps and front wheel drive and he was able to drive home in front wheel drive without having to replace the axle.

Rzeppa
12-06-2011, 01:59 PM
Apples to oranges! True fact that when drums are properly adjusted they provide sufficient stopping power. The variance is that disc's do not need to be adjusted and will always have predictable and sufficient stopping power while the drums will decline after every stop until adjusted again.

I have been trying to stay out of this never-ending debate, but my personal experience is thus:

(1) Disk brakes can overheat and fade. It happened to me when I was getting strapped off Fins in '02 when I had no drive shafts. Coming down into town from Sand flats recreation area I almost lit my pads on fire! They were never the same after that, and it wore the rotors way down too.

(2) Drums brakes can still work when they get wet. When we did the DATD run down Hackett Gulch in '01, we crossed the South Platte (top of tire-deep) and went back via Metberry. I had heard so much about how drums don't work when they get wet that I immediately tried them after I got to shore and to my surprise they worked just fine!

(3) My FJ45 has the 3" drums all around, and has WAY more stopping power than any disk brake vehicle I have ever driven. I think that's why they use drums on big rigs - if you make them big enough they work great.

(4) My shoes seem to last about twice as long as pads.

The above is just my personal experience, not what experts say or anything I have read. I will say that not having to adjust disk brakes is the main reason disks appeal to me. But once my cylinders are properly adjusted they normally last at least as long as the interval that a set of pads have to be replaced.

Dr. Schlegs
12-06-2011, 03:23 PM
You don't have to be gangsta to talk gangsta, evidenced by the fact that 99% of all of the "gangstas" you see out there are wannabes.

That explains why you have been sagging your Wrangles, and doing the Gangsta lean in the Porsche.

rover67
12-06-2011, 03:40 PM
The conversion looks great Ricardo! Nice write up! How do you like it?

RicardoJM
12-06-2011, 04:34 PM
The conversion looks great Ricardo! Nice write up! How do you like it?

Thanks for bringing this thread back on track:D. My master cylinder had gone bad and was not sending fluid to the rear. I could have replaced the master and gone on with life just fine, but because I was going to be spending some money, I decided to go to discs.

I've been running it a couple of weeks and I do like it. I still have not installed the proportioning valve. On the snow/ice if I hit the brakes hard, the rears locking up first is an issue as the back end will kick out. On dry roads, even though the rears lock up first - it tracks straight and true. Being that I drive my 40 like an old lady heading to church the only times I've hit the brakes hard have been when I want to. I'll install the valve and it will be better.

Would I recommend it to someone else? Meh, it is certainly not in the same category of improvement as upgrading to Roundeyes or installing comfortable seats - these are things that really made a big difference from my perspective and I would recommend without reservation:D.

The conversion is simple, well within the capabilities of anyone willing to put in some work. Disc brakes are less maintenance than drums and there is a certain charm to "set it and forget it" add to that the fact that all the components are all new and should last a long time - I'm not going to go back to drums. If someone was needing to do work on their brakes, i.e. a cylinder burst, the springs broke, or the shoes need to be replaced - things where you are going to be spending money - it would be an opportune time to make the switch and certainly something to consider.

Air Randy
12-06-2011, 06:22 PM
I have been trying to stay out of this never-ending debate, but my personal experience is thus:

(1) Disk brakes can overheat and fade. It happened to me when I was getting strapped off Fins in '02 when I had no drive shafts. Coming down into town from Sand flats recreation area I almost lit my pads on fire! They were never the same after that, and it wore the rotors way down too.

(2) Drums brakes can still work when they get wet. When we did the DATD run down Hackett Gulch in '01, we crossed the South Platte (top of tire-deep) and went back via Metberry. I had heard so much about how drums don't work when they get wet that I immediately tried them after I got to shore and to my surprise they worked just fine!

(3) My FJ45 has the 3" drums all around, and has WAY more stopping power than any disk brake vehicle I have ever driven. I think that's why they use drums on big rigs - if you make them big enough they work great.

(4) My shoes seem to last about twice as long as pads.

The above is just my personal experience, not what experts say or anything I have read. I will say that not having to adjust disk brakes is the main reason disks appeal to me. But once my cylinders are properly adjusted they normally last at least as long as the interval that a set of pads have to be replaced.

See UB? Thats what I was talking about :D

Uncle Ben
12-06-2011, 10:08 PM
See UB? Thats what I was talking about :D

I knew exactly what you were talking about! :rolleyes: I started wasting time replying to the post and came to my senses and deleted my reply....all is good! :thumb: