Author Topic: Brake Master Cylinder Swap  (Read 5269 times)

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alaskan ogre

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Brake Master Cylinder Swap
« on: October 18, 2010, 09:23:37 AM »
Looking into swapping out the Daihatsu Master Cylinder with a Toyota unit that uses a bigger piston and booster for better stopping power with the larger tires. Has anyone done such as swap?


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Re:Brake Master Cylinder Swap
« Reply #1 on: October 19, 2010, 08:07:18 AM »
I replaced my brakes for the orange Feroza . I bought a surplus hilux unit
and I just used the big vacuum booster ( the black round thing) .
Did\'nt replace the brake lines anymore. It was a big improvement.
Just make sure that the holes are the same.

alaskan ogre

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Re:Brake Master Cylinder Swap
« Reply #2 on: November 28, 2010, 02:12:15 PM »
That\'s great to hear. I did some measurements on mine and because I now have a clutch master cylinder after swapping the motor/trans to Toyota stuff the Toyota unit won\'t fit because the booster is too big. I need to do some more looking, maybe something out of a Supra or Celica.


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Re:Brake Master Cylinder Swap
« Reply #3 on: December 02, 2010, 08:31:48 PM »
What year Hilux was yours of Mon?
Did you take the booster only or the booster and Master cylinder together?

I have issues with mine having really soft pedal at times.

I\'ll be sitting at the lights and especially down hill, the pedal will quite steadily (30 seconds or so) run to the floor.

I haven\'t been loosing fluid, but its disconcerting having to pull the handbrake on everytime I pull up at the lights.

It improves from time to time which is weird and other times it will do it when I am braking heavily which is worse, major case of brake fade.

Sorry for the hijack, but I always try to research as much as I can from peoplpe who have made mods that work.


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Re:Brake Master Cylinder Swap
« Reply #4 on: December 02, 2010, 09:18:24 PM »
Maybe stupid Q but have you Bled the brakes ?
You are asking about MOD\'s what have you MODed do you run larger tires?


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Re:Brake Master Cylinder Swap
« Reply #5 on: December 02, 2010, 09:26:38 PM »
Yes I have bled the brakes, though the more I think about it I think I might do it again.
(brake fluid is cheap)

I have 40mm lifted tough dog springs with longer shocks to match with adjustable rears.
Wound up standard torsion bars, 2\" bodylift and running 235x75x15 Hankook MT.

It\'s fairly standard because I have to drive it everyday to work, but eventually I will fozzy lock the front and rear diffs and drive it less.
Also seriously considering a re-power from an Isuzu Mu 2.8TD.
I have even looked at gearing for this I think I will be able to run 31s still with improved gearing over standard on 235s.

But all this will wait until my partner gets a job and I can afford to spend money on my toy truck instead of the rent.


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Re:Brake Master Cylinder Swap
« Reply #6 on: December 11, 2010, 02:39:57 AM »
Hi, Im having the same trouble with my brakes/ I would really like to swap out my master cylinder. Mon,would like to know what toyota m/c and booster you swapped please:silly:

alaskan ogre

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Re: Brake Master Cylinder Swap
« Reply #7 on: August 07, 2011, 05:33:32 PM »
Now that I\'ve moved the clutch Master Cylinder inside the cab I have room to do the swap. Here\'s what I\'ve found so far.

Almost all Toyota\'s use the same bolt pattern and line threads and since Monmendoza has already swapped in a Hilux MC I\'m assuming that most Toyota MC\'s will fit. Now I just need to find one with a larger bore and booster than the one in the Hilux\'s.

I did some research this morning and found that Toyota has Master Cylinders that have the following piston sizes (the Daihatsu MC is 7/8\"):


Toyota changed from smaller calipers to larger bore calipers at the same time they upgraded the Master Cylinder bore sizes but not the same amount. This changed the hydraulic ratio of the caliper piston to the master cylinder piston from 7:1 to 5.7:1 on the newer models to make the pedal fell stiffer. To increase breaking efficiency they began using dual diaphragm boosters.


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Re: Brake Master Cylinder Swap
« Reply #8 on: August 08, 2011, 11:01:28 AM »
sorry was not able to reply questions posted 9 months ago.
I did\'nt notice it.
I have no idea for what toyota model it was. It was a surplus
unit. The junk shop selling it just said it was for a toyota
and we just compared it to the feroza brake booster and the
screw holes fit. and thats it.

I think you have to remove your brake booster and bring it to
any surplus shops. The thing you should have to watch out are holes that attaches
to the piston and the lenght of travel and of course preferably
it should be a bigger booster so that braking becomes easier. :)

Come to think of it, I also replaced the brake booster of my 4runner
and my pajero less than 6 months ago. I don\'t even know what
brand or model it came from. But they seems to have either 4 holes
or 2 holes and you consider piston travel too. As long as they
fit, It seems that you won\'t have any problem. Of course since
I don\'t know how to calculate the actual requirements, what I did
was go for a bigger box. I hope this info helps. :)

alaskan ogre

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Re: Brake Master Cylinder Swap
« Reply #9 on: August 08, 2011, 08:46:30 PM »
I have looked at a ton of pictures for various makes and models and cannot find any larger bore mc\'s that have the same mounting ears that the Daihatsu mc has. It looks like all of the larger piston Toyota Master Cylinders use 4 bolts to mount it to the booster.

The Daihatsu Booster also looks like it\'s only a single diaphragm type. A dual diaphragm booster would be a significant advantage. Replacing both the diaphragm and master cylinder would be the ideal upgrade.

The Master Cylinder with the Dual Diaphragm Booster from the 90\'s V6 or 4 Cylinder Turbo Pickups and 4Runners seem to be recommended the most for increased stopping power. We just need to find a dual diaphragm booster that is small enough in diameter to fit the Rocky.

Single Diaphragm:

Double Diaphragm:

alaskan ogre

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Re: Brake Master Cylinder Swap
« Reply #10 on: August 08, 2011, 08:56:06 PM »
Internal drawing:


alaskan ogre

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Re: Brake Master Cylinder Swap
« Reply #11 on: August 08, 2011, 09:37:33 PM »
I just measured the stock Booster and it\'s 8\" in diameter and there\'s no more than another inch to spare before the booster hits the steering shaft. Good thing is that this is the same problem that owners of the older Toyota Pickups have and can be overcome by adding a short spacer between the Booster and Firewall.

Here are 3 of the Boosters available:

1985 Toyota Pickup with the 22RTE Engine (Turbo) (8-3/4\" Diameter)

1993 Toyota Pickup 3.0 v6 (8-3/4\" Diameter)

1996 Toyota T100 3.4 v6 (9 3/4\" Diameter)

alaskan ogre

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Re: Brake Master Cylinder Swap
« Reply #12 on: August 09, 2011, 03:15:32 AM »
Pic of Daihatsu Booster and Master Cylinder (MC mounting bolt holes are exactly 4\" on Center):

Interior side of Booster with Pedal Rod (Bolt pattern is 3.125\" on center horizontal and 2.375\" on center vertically):

Drivers side pic of Master Cylinder:

Offline Ray038

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Re: Brake Master Cylinder Swap
« Reply #13 on: September 08, 2011, 10:48:10 PM »
I fix my soft pedal on my Rocky I took the master cylinder off the brake booster their a seal on the brake booster where push rod for the booster.The seal had some cracks in were air get out so I put RV silcone to seal up the leak it work great now no more soft pedal

alaskan ogre

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Re: Brake Master Cylinder Swap
« Reply #14 on: September 14, 2011, 01:00:26 AM »
Ok, I have this all figured out now and it\'s going to provide a significant improvement over stock if you\'re running larger tires or towing.

I picked up a Master Cylinder and Dual Diaphragm Booster off a 1992 Toyota 4Runner. I\'ll post interchange info later.


The bolt pattern for the 4 studs is slightly larger than the Daihatsu pattern. The large hole in the firewall is perfect. I was going to just re-drill the firewall to the new pattern but after looking under the dash this cannot without significant work to the mounting plate. In this pic you can see how close the nuts are to the brackets that hold the pedals in.


The rod that connects the pedal to the booster is longer than the Daihatsu unit so I decided to just build an adapter plate/spacer. This would also allow for better clearance between the Booster and steering column.

The Daihatsu and Toyota brake line threads are the same. The front brake lines attach to a \"T\" which has a line going to the front of the Toyota Master Cylinder (backwards from the Daiahstu MC)

A couple pics of it installed:



I\'ll post pics of the adapter I made next week. I need to pull it back out and clean up the welds after I return from a wedding in Seattle this weekend. It\'ll be going into my big black Rocky then.