Minitruck Brake Booster Marlin Master Cylinder Writeup

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1973Guppie

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Thought I would do a short writup in one thread that shows my solution to my MC and brake booster going bad and what I did for a solution. I found alot of info in the threads but none in one place.


PARTS:

Booster: p#53-2460, from 81 toyota pickup
http://www.partsamerica.com/productdetail.aspx?MfrCode=A1C&MfrPartNumber=532460

power brake check valve: p#80190, help! item from local autoparts store
http://www.partsamerica.com/productdetail.aspx?MfrCode=RNB&MfrPartNumber=80190

Master Cylinder: From Marlin Crawler, FJ80 non usa master made to be used on 4 whl discs.
http://www.marlincrawler.com/htm/brakes/mcylinder.htm

* p#'s are standard and can be looked up at any autozone, kragen's, etc.


Findings:

- flaring brake lines is a bitch, get a good tool and a lot of tube, the black colored tube flares easier and bends much easier than the silver stuff. It takes awhile to get a flare that will hold. I have been told that the hydraulic flaring tools are the way to go if you are going to do a bunch of flares, but they are expensive. **see my notes below on flaring....

- take a good look at your booster when replacing a leaky MC. My MC was leaking just a bit between the MC and booster. After I got the whole shebang back together with the old booster I found out that the brake fluid had leaked into the old booster and had killed the seals. If your booster is old, and soaked from brake fluid, you may want to consider just replacing it.

- when installing the booster, make sure your pads are not dragging. If so they will smoke like mine did! :) I ended up having to space the MC away from the booster about 1/4 inch using some M10 nuts, worked fine, not the cleanest solution but hey, it worked. Another cleaner solution may be to either pull the booster rod and shorten it, or make custom plate spacer out of 1/4 plate. I could not get mine out and didn't want to break anything so I went with the spacing solution. The other mc rods i had from my older booster would not work as they were thicker than the new 81 minitruck booster rod. I tested to make sure things weren't dragging by letting the car roll down the driveway. you may not have to do any of this with the stock or another booster. The marlin MC flange is thin, and the stock MC flange is much thicker, so it just dpends on the setup you have.

- check valve: found one at the local parts store and just put together some hose attachments to make it work. I used some step down pvc couplers to move from a larger hose to a smaller one and vice versa. I did some research and the check valve IS NECESSARY. Basically the check valve ALLOWS vacuum through it but not pressure, so if your engine dies, your booster will not lose vacuum and you will have at least a few pumps of your booster to help you stop. I thought this was important.


Conclusion: This setup is much nicer than my stock setup. Wow, quite a difference. The above booster is a double diaphram unit, not a single diaphram unit like stock. The bigger booster gives much more boost. There is a nice bit of play at the top of the pedal which is nice, but I can now stop on a dime. I am very happy with the setup, attached are some pics.

Let me know if anyone has any questions, or if I missed anything.

Noah
DSC00939.webp
DSC00940.webp
DSC00941.webp
 
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You didn't mention your rear proportioning valve. Is it necessary with the FJ80 MC designed for 4wheel discs?

I just replaced my booster after doing the MC a while back. It's almost scary how touchy the brakes are now. If I try, I can lock the right rear, so I'm wondering about a prop valve.

Phil
 
the prop valve is necessary when running 4 whl discs, has nothing to do with the kind of master cylinder you are running, checkout summit racing or jegs, they sell a couple types, easy install and they do help keep the rear from locking up. I usually just set mine at 50% and leave it be, has worked for awhile now.

Noah
 
Just wanted to give out a BIG THANK YOU for this thread.

Using this thread I ordered a

Master Cylinder Aisin #BMT-081
Reman Booster #53-2460
check valve #80190

all from CarQuest.

With some spacing issues taken care of my 40 is now stopping on a dime.

Thanks 1973Guppie and thanks MUD!
 
Guppie did you switch over from a single circuit non-boosted master? When I do this upgrade will I have to build new brake lines since I have a single circuit with master only? and what did the parts cost you too?
 
on my 76 we were able to use existing brake lines to the master cylinder with alittle manipulation.;)
 
Just wanted to give out a BIG THANK YOU for this thread.

Using this thread I ordered a

Master Cylinder Aisin #BMT-081
Reman Booster #53-2460
check valve #80190

all from CarQuest.

With some spacing issues taken care of my 40 is now stopping on a dime.

Thanks 1973Guppie and thanks MUD!

glad it worked out for you. With the double diaphram booster it really increases the braking, I have to be a bit careful in my 40 now because the brakes work so well.

Noah
 
Guppie did you switch over from a single circuit non-boosted master? When I do this upgrade will I have to build new brake lines since I have a single circuit with master only? and what did the parts cost you too?

no, mine is a 73 and already had boosted brakes stock. On your 67 you are going to have to deal with the rib in your firewall. You will probably have to use an adapter and ?. I have no idea if this setup would work for you or not. Not sure either if you're stock b lines will thread right in, I don't think so as the early year brake line fittings are different than later IIRC.

Noah
 
one note that I wanted to add here on flaring brake lines.

When cutting the brake line, use a grinder with a cutoff wheel. The reason for this is that the little cutting wheels that come with the flaring kits (the small ones you go round and round with the small cutoff wheel) actually work harden the metal and make it very hard to flare. My friend told me this and sure enough, once I used the grinder to cut the brake line and THEN use the flaring tool, I had much better sucess. Something to think about.......

Noah
 
Did the clutch master cylinder bolt get in the way? I replaced mine with a booster from a 4runner and had clearance issues with the bolt closest to the booster.

Chuck
 
Did the clutch master cylinder bolt get in the way? I replaced mine with a booster from a 4runner and had clearance issues with the bolt closest to the booster.

Chuck

negative
 
Spacer

Hi Noah,

I am following your lead here and had a question about the booster rod that sticks in the cab and attaches to the brake petal lever. The booster I got does fit but, the rod seems to be a good bit longer. Did you have to modify it?

I used a booster out of a 91 Landcruiser in my 40. I had the same situation as you. A friend is a fabricator at a sawmill machinery plant and got a 3/4" thick piece of aluminum for me to fab a spacer with. Later when I was junkyard hopping for parts I ran across a mid to late 80's mini truck that had a 3/4" thick spacer between the firewall and the booster. Check it out, see if what you need may be a 3/4" spacer or close to that.

Don
 
I'm running a mini booster with an 80 series MC (I think). IIRC, it was all pretty much a bolt on deal. I do not run the wildwood proportioning valve. I have 40 discs up front on mini knuckles (6 shooter) and GM discs and calipers in the rear. No issues that I can tell, though I haven't locked anything up yet. Maybe I should try! :)
 
TTT with this thread,Just wanted to post up for some folks to see.Good info here,Thanks Guppie!
Anyone running this setup with a stock engine and an early firewall divider??
 
I used a booster out of a 91 Landcruiser in my 40. I had the same situation as you. A friend is a fabricator at a sawmill machinery plant and got a 3/4" thick piece of aluminum for me to fab a spacer with. Later when I was junkyard hopping for parts I ran across a mid to late 80's mini truck that had a 3/4" thick spacer between the firewall and the booster. Check it out, see if what you need may be a 3/4" spacer or close to that.

Don

When I re-did mine, I nabbed a booster out of a mini ( '92 ) that had an aluminum plate that went between it, and the firewall. Used a Downey " Big Bore " 1 1/16 bore MC, stops good without a porportioning valve ( S10 Calipers on rear ). Guppies right, look at the inside of the booster behind the MC. My old one was soaked. Night and Day difference. Al
 
Doing all this changeing with the booster.and i notice you are running a v-8 .would there be room in my 40 engine compartment to do the same thing ihave a2-f in it and a s-10 mastercylinder in it ,no booster right now the master cylinder is close to the carb (weber )
 

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