Master Cylinder upgrade options

[bikerjosh]

Wondering if anyone knows what are the best options for an MC upgrade?
My t4r is a 98 with a rear disk conversion (abs disconnected when PO switched to crmo axles on the rear). My brakes were always on the edge meaning a little squishy (technical term) with more pedal travel than normal. After my 231 Tundra upgrade I, this problem is even more pronounced. Bled the system two times and will bleed it again this weekend when my brother is available. Not getting any air bubbles out of the lines anymore so I think this is what I', stuck with. I've heard swapping out to a Tundra MC (aftermarket ones are pretty reasonable) or going with a mid 80's Chevy 1-ton MC will push more fluid and return a firmer pedal.

As an aside the new brakes work great, it's just that they take a while to make contact with the rotors and it feels like if I really tried I could get the pedal to the floor if I tried.

thanks :hiding:

 

[the great him]

you could use a 1" bore MC from an fzj80...

 

[bikerjosh]

you could use a 1" bore MC from an fzj80...

What years, 93 appears to be the last year of single MCs I believe? Looks like T100 MC are also 1" bore.
thanks

 

[fire931]

Just to make sure since you have the rear disc conversion, have you checked to make sure the calipers aren't getting pushed back in thus causing the long pedal travel?

 

[driffter33]

76 chevy blazer $36.00 1 1/8" bore very slight modifications needed. For me this waas a huge improvement, but as you know I still need to try a proportioning valve..

 

[bikerjosh]

76 chevy blazer $36.00 1 1/8" bore very slight modifications needed. For me this waas a huge improvement, but as you know I still need to try a proportioning valve..

Modification wise are you talking about an adapter plate so you can bolt it up?
I found some info on Rockstomper's kit, but they seem to be shut down.
josh

 

[driffter33]

No adaptor needed. All I had to do was slightly oval out the mounting holes on the new MC and there is a pointed ajuster nut on the end of the brake pedle push rod @ the point that pushed on the MC. I removed that ajuster and bolted it up simple simon. I also had to braded brake hoses made up ahead of time with the chevy MC fittings on one end and the toyota on the other I think they were 18" around $50. You can check my build thread for pics of how it all came togeather.

 

[bikerjosh]

Master Cylinder Options for disk conversions

No adaptor needed. All I had to do was slightly oval out the mounting holes on the new MC and there is a pointed ajuster nut on the end of the brake pedle push rod @ the point that pushed on the MC. I removed that ajuster and bolted it up simple simon. I also had to braded brake hoses made up ahead of time with the chevy MC fittings on one end and the toyota on the other I think they were 18" around $50. You can check my build thread for pics of how it all came togeather.

Hey Drifter
I took a look at post #26, that has the pictures of your blazer MC, what is that round piece that has 3 lines going into (looks like it might be on the left side of the engine compartment)?
thanks

 

[Mf Baker]

my buddys accord has big brakes front and rear, he switched over to this wilwood and has had no problems. this would definitely solve your problem, if not make a new one by making the pedal too stiff, lol!

 

[Singtoe]

For what it is worth, I have a Sequoia Master cylinder. It was designed by Toyota for 4wheel disk brakes as the Sequoia has 4 wheel disk brakes.

I did a little research and it is slightly different.

But for what it is worth. The Sequoia Master cylinder is 15/16" bore diameter and the 4runner is 1" bore diameter.


You should be fine using the stock MC.

The bigger mc should give you a firmer shorter brake pedal. If you go down in size, it will give you easier brake pedal but will be soft and have longer throw to it.


I think you need to get rid of the ABS Pump if your not using it.

 

[bikerjosh]

For what it is worth, I have a Sequoia Master cylinder. It was designed by Toyota for 4wheel disk brakes as the Sequoia has 4 wheel disk brakes.

I did a little research and it is slightly different.

But for what it is worth. The Sequoia Master cylinder is 15/16" bore diameter and the 4runner is 1" bore diameter.


You should be fine using the stock MC.

The bigger mc should give you a firmer shorter brake pedal. If you go down in size, it will give you easier brake pedal but will be soft and have longer throw to it.


I think you need to get rid of the ABS Pump if your not using it.

I was under the impression that the stock MC on the 98 4runner is 13/16" ? My reason for going to a larger MC bore was to bring the pedal up reduce the need to pump it. Am I corn-fused this would work?:lookout:

josh

 

[Singtoe]

I was under the impression that the stock MC on the 98 4runner is 13/16" ? My reason for going to a larger MC bore was to bring the pedal up reduce the need to pump it. Am I corn-fused this would work?:lookout:

josh

I am cornfused too. But every resorce i have looked up says the MC is 1". What is cornfusing is that it is measured in inches verses millimeters.

I think the pre 95 toyos had the 13/16" MC's.

 

[Nelsonmd]

corn

 

[ChildrenOfBodom]

You can use a T100 master if you change your booster, too.

The 4Runner master has 2 bolts and will not allow a T100 or 2nd gen 4runner master to bolt up.

The T100 booster gives you the ability to make 4 bolt masters fit. The 95 4Runner w/ ABS had a 1 1/16" bore. Thats what i'm gonna go with.

Just make sure you get the dual diaphragm booster and not the single diaphragm

 

[Rockdawg84]

My reason for going to a larger MC bore was to bring the pedal up reduce the need to pump it. :lookout:

josh

Josh, just a question. Do you have a residual valve in the rear brake line. if not that could be your problem. Unless you have the Front Range off Road conversion where you also have a full float rear then you need a residual valve. Here is a quote from FROR fabs website.
"We often get asked "What other benefits does a Full-Floating axle have, why should I convert?" Well, like they say, a picture is worth 1,000 words. Here's the left rear axle shaft in our Tacoma, after just 3 trail runs. This runout translates to about 3/8-1/2" wobble in the tire. This not only wears tires unevenly, but rapidly destroys a drum or disk brake (imagine a rotor with .120 runout!) and it eats wheel bearings for lunch. With a Full-Floating axle, this simply cannot happen. And no, the truck was not jumped, or hopped on obstacles."

obviously they want to sell their kit (which I would love to have someday) but the point is that without a residual valve the wobble in the rear axle will push the pads away from the rotor and take more fluid to push the pads back onto the rotor, thus more pedal travel or even 2 pumps. before you go swapping out a master cylinder make sure that you don't have to. Residual valves are much easier to put inline that adapting a new master cylinder. Good luck

 

[driffter33]

Hey Drifter
I took a look at post #26, that has the pictures of your blazer MC, what is that round piece that has 3 lines going into (looks like it might be on the left side of the engine compartment)?
thanks

That is where my ABS pump used to be. it is just a T for the 3 front brake lines. next to it you can see the in line coupler for the rear brakes.

 

[driffter33]

So if you look at post #74 of my build thread you can see what I did for the residual valve. I installed a 2psi vale as all the reading I did said use the 2psi for disk brakes and the 11psi for drum. it has made an improvement, but not as much as the gm master cylinder. i am tempted to try the 11psi i carry a temp gun and can keep an eye on brake temps witch would let me know if there is to much drag on the rears. How ever the sweet spot might just be to use the 2psi in conjunction with a proportioning valve.
It would bee nice to know what the factory recommended brake system pressures for a 85 Cadillac Eldorado are. knowing that I have more weight and bigger tires and the same calipers. I think it would stand true that I would want to increase that pressure some. with this info one could look for a prop. valve that would run the rear calipers in that pressure range. Some day I may have time to do the research.
If you weren't confused before you should be now I hope this helps.

 

[Singtoe]

Josh, just a question. Do you have a residual valve in the rear brake line. if not that could be your problem. Unless you have the Front Range off Road conversion where you also have a full float rear then you need a residual valve. Here is a quote from FROR fabs website.
"We often get asked "What other benefits does a Full-Floating axle have, why should I convert?" Well, like they say, a picture is worth 1,000 words. Here's the left rear axle shaft in our Tacoma, after just 3 trail runs. This runout translates to about 3/8-1/2" wobble in the tire. This not only wears tires unevenly, but rapidly destroys a drum or disk brake (imagine a rotor with .120 runout!) and it eats wheel bearings for lunch. With a Full-Floating axle, this simply cannot happen. And no, the truck was not jumped, or hopped on obstacles."

obviously they want to sell their kit (which I would love to have someday) but the point is that without a residual valve the wobble in the rear axle will push the pads away from the rotor and take more fluid to push the pads back onto the rotor, thus more pedal travel or even 2 pumps. before you go swapping out a master cylinder make sure that you don't have to. Residual valves are much easier to put inline that adapting a new master cylinder. Good luck

4x4 4runners don't have residual valves. The 4 wheel disk brake Sequoia does not have a residual valves. Neither of one of them have proportion valves either.

If you have run out that translate to 3/8 to 1/2, you need to replace your axle. If it coming from the bearing, then it will need to be replaced to0.


Full floating rearing ends are necessary if your going to carry heavy loads. IE -more than 3/4 tons.

I like full floating rear ends as they are much stronger but for our 4runner, it is over kill and expensive.

If it were on a Taco, I would consider it as they are more likely to get overloaded with cargo and what not.

Which reminds me of a funny story. I was in Thailand several years ago and during the last 2 days of my vacation out there coming back from a Discotec, a Toyota pick up with a cargo cage that went up over the cab was full of pineapples. He ran a stop sign, and I t-boned him.

I was freaking out, I had been drinking earlier and shouldn't have been driving and I thought I was going to jail. Cops came, looked at the seriously overloaded truck and gave the truck driver a ticket and left. 24 hours later, I was on a plane back to the States.

Here is a picture, not mine but similar to what I hit.

 

[awdjunkies]

Crazy story, interesting the way they run (3rd world)countries. In this case, to your advantage...

 

[bikerjosh]

Brake issues

Thanks Singtoe, so not sure where I came up with the idea that the 4runner MC was different/smaller than 1", but every resource I have looked up recently says it is a 1".

I am curious why I would need to remove the ABS pump? If the main ABS fuse has been removed, I would have thought it would just act as a pass through?

I have bled the system (I can't remember how many times) and no bubbles are coming out, but the pedal is still mushy.:ybrick:

Hey driffter33 any reason you didn't try to mount the residual valve closer to the MC? I was reading up on them yesterday and many sources reccommend mounting them as close to the MC as possible.

josh

For what it is worth, I have a Sequoia Master cylinder. It was designed by Toyota for 4wheel disk brakes as the Sequoia has 4 wheel disk brakes.

I did a little research and it is slightly different.

But for what it is worth. The Sequoia Master cylinder is 15/16" bore diameter and the 4runner is 1" bore diameter.


You should be fine using the stock MC.

The bigger mc should give you a firmer shorter brake pedal. If you go down in size, it will give you easier brake pedal but will be soft and have longer throw to it.


I think you need to get rid of the ABS Pump if your not using it.