Rear Disk Brake Conversion Pt 1

[Singtoe]

I have not had anytime to do the conversion myself but it looks like getting the parts for a 4th gen 4runner (same as Sequoia) won't work. Well. not bolt on anyway.

Our axles use a bearing pressed on the the axle which directly fitted to our axle housing.

The 4th gen 4runner uses a bearing carrier. The axle is pressed into the carrier and it is bolted on the the axle housing.

It looks to be a double row bearing instead of our single row bearing.

I don't believe that the is enough space on our axles between the hub and the backing plate to fit the parking brake shoes.

In order to make it work, which I will try one day, would have to take some caliper bracket fabrication and some time.

 

[Kurtis]

Normally in vehicles the Master Cylinder is different from rear disc brakes to drum. The drum Master Cylinder sends more power/potential to the rear brake system. When you swap out the rear drums for disc there is a possibility of the rear brakes locking up. Have you noticed the rear brakes sticking at all? I was thinking about this the other day. How did you go about deciding what rotors and calipers to use? Trial and error?

 

[bikerjosh]

x2 on Gerdo's suggestion. DO NOT use an electric line lock.
I have the eldo set up, without parking brake tabs and will try plumbing a manual line lock as soon as I fix my leaky residual pressure valve install.
josh

 

[Gerdo]

Disks require more volume of fluid than drums. This may be why you have the feeling that they are a little soft, not enough volume being pushed to the back.

On the other hand, IF the backs are too powerful and tend to lock, you could add a proportioning valve Proportioning Valves - Proportioning Valve . This will allow you to dial in the balance between the fronts and the backs.

 

[Rockdawg84]

Normally in vehicles the Master Cylinder is different from rear disc brakes to drum. The drum Master Cylinder sends more power/potential to the rear brake system. When you swap out the rear drums for disc there is a possibility of the rear brakes locking up. Have you noticed the rear brakes sticking at all? I was thinking about this the other day. How did you go about deciding what rotors and calipers to use? Trial and error?

I am not experiencing any sticking or the rear locking up before the front. I believe that is because the rear calipers are much smaller than the fronts and that they make a good balance between the two. I originally got the Idea from some guys over on Pirate4x4 and that was my starting point, then lots of research on the web (google is amazing) then with a good base line I went to Autozone and had them start pulling different rotors and calipers till I found a combo I was happy with. So far I am stoked about this. Last night I did some research and I think I have found a 1-1/8 master cylinder that will bolt up. chevy avalanche believe it or not

 

[Rockdawg84]

I have not had anytime to do the conversion myself but it looks like getting the parts for a 4th gen 4runner (same as Sequoia) won't work. Well. not bolt on anyway.

Our axles use a bearing pressed on the the axle which directly fitted to our axle housing.

The 4th gen 4runner uses a bearing carrier. The axle is pressed into the carrier and it is bolted on the the axle housing.

It looks to be a double row bearing instead of our single row bearing.

I don't believe that the is enough space on our axles between the hub and the backing plate to fit the parking brake shoes.

In order to make it work, which I will try one day, would have to take some caliper bracket fabrication and some time.

Thanks that is good info. I believe that I can work out the mechanical e-brake pretty easy. Only been a couple of days and already I am realizing how much I use it and miss it. Part 2 coming soon.

 

[A.Wilson013]

Part 2 coming soon.

:snacker:

 

[Gerdo]

Awesome mod. Other than fabbing a couple of mounts, a pretty simple install.

 

[Rockdawg84]

Awesome mod. Other than fabbing a couple of mounts, a pretty simple install.

exactly:guitar2:

 

[iswingping]

great tech w/ photos!

That is awesome information! I am unsure of the later model drum to disc, but I just swapped in a Crown Vic front end on an old F100. There was a residual valve that is accessed where the lines hook into the master cylinder that needed to be removed. Basically, it is a spring and check ball that was located behind the brass fitting where the double flare sits. I don't know if this would cause a softer pedal or not, but both Wilwood and Speedway indicated that drums require roughly 10 lbs of residual pressure while discs are ok with 2 lbs. It may end up being a $0 fix.

 

[Rockdawg84]

That is awesome information! I am unsure of the later model drum to disc, but I just swapped in a Crown Vic front end on an old F100. There was a residual valve that is accessed where the lines hook into the master cylinder that needed to be removed. Basically, it is a spring and check ball that was located behind the brass fitting where the double flare sits. I don't know if this would cause a softer pedal or not, but both Wilwood and Speedway indicated that drums require roughly 10 lbs of residual pressure while discs are ok with 2 lbs. It may end up being a $0 fix.

Thanks. I really think my long pedal travel has to do with my master cylinder being too small now that I have upgraded both the front calipers and changed the rear to calipers instead of wheel cylinders. I just simply have too much volume in the system for the 1" bore Master to push so I am going to upgrade to a 1-1/8th bore master cylinder. I believe that the pedal will come up and be much firmer without being too hard.

 

[Singtoe]

For what it is worth-

The 4runner master cylinder is 1" (25.4mm) bore. The Sequoia, which from the factory uses the 231 front calipers and rear disk brakes has a master cylinder with a bore of 15/16" (23.81mm) bore.

 

[bikerjosh]

I am not experiencing any sticking or the rear locking up before the front. I believe that is because the rear calipers are much smaller than the fronts and that they make a good balance between the two. I originally got the Idea from some guys over on Pirate4x4 and that was my starting point, then lots of research on the web (google is amazing) then with a good base line I went to Autozone and had them start pulling different rotors and calipers till I found a combo I was happy with. So far I am stoked about this. Last night I did some research and I think I have found a 1-1/8 master cylinder that will bolt up. chevy avalanche believe it or not

I believe a 76' Blazer will work as well. About $35 at Napa.

 

[jblazy18]

so when can we expect Part II of the conversion?!... im going to do this as soon as the weather gets warmer here in illinois, my rear drum brakes arent even engaging and the e-brake mechanism on the drums is rusted together... did you install a residual valve and still need a bigger bore mc?...

 

[bikerjosh]

Residual valve

Yep, put in a 2lb residual valve w/hardlines first on the advice of a local offroad custom shop. It may have helped, but still need more. I have to bench bleed the 76' blazer MC then swap that in. Currently working on a meth injection system so the brake MC has to wait. Yep, making the truck faster before making it stop better. With my life insurance premiums paid up and a new living trust seems to make perfect sense. LOL.
Josh

 

[Rockdawg84]

so when can we expect Part II of the conversion?!... im going to do this as soon as the weather gets warmer here in illinois, my rear drum brakes arent even engaging and the e-brake mechanism on the drums is rusted together... did you install a residual valve and still need a bigger bore mc?...

Soon, I really like the conversion but haven't had time to work on part 2 yet but I am confident that Iwll be able to make it work.

 

[4Running Daily]

Soon, I really like the conversion but haven't had time to work on part 2 yet but I am confident that Iwll be able to make it work.

And I will be starting my disk brake conversion soon.

I am confident in his abilities to get the E-Brake working as well.

 

[Tucson4runner]

Soon, I really like the conversion but haven't had time to work on part 2 yet but I am confident that Iwll be able to make it work.

What's the total cost your in so far?

 

[Rockdawg84]

What's the total cost your in so far?

Because I bought everything new I am currently sitting at about 550 and prob have another 50 to 80 to get the ebrakes working correctly. But if you hit the pick and pull I think this could be done for a lot less.

 

[4Running Daily]

I'm aiming for 400.