Request for advice on 76 FJ40 Brake Master (1 Viewer)

[thebigredrocker]

Background: I am restoring a 76 that has been torn apart since about 1987. I purchased this project in 2006 with most of the parts in boxes. It appears the master had leaked fluid down the booster. The odometer reads 25,000 miles

Does anyone know a source for just the rubber piston seals?

If not would I be wasting my time just honeing the cylinder and using the seals I have.

Also what are the chances the pressure warning switches are still ok? They do appear dirty inside. Not sure if they can be soaked to clean them up any.

Thanks for your time

 

[78fj40mg]

My opinion is to purchase a new MC. No use in trying to rebuild a corroded MC and risking your life.

 

[lostmarbles]

AFAIK you can't buy the seals by themselves.

Putting a stainless liner in your master and fitting a new kit is a good option though in my opinion. I'm certainly happy with having gone down that route:

 

[snaggletto]

I just got in touch with Beno and ordered a new one from Toyota for my '76. List is $269, mud price is ~$200. This is for the complete assembly including the brake switches.

 

[thebigredrocker]

Well I got a new Brake MC today. Thanks for the advice!

Now I am wondering if I should attempt to re-use my old proportion valve. It was full of gunk and has some nicks in the piston. I cleaned it up as best I can. The rubber is still reasonably pliable. I am guessing new seals don't exist.

Also, after encountering all the crud in the Brake MC & Prop Valve I am wondering if crud is present in my brake lines. Is there a trick to flushing the lines out? How will the front disks and rear drums perform if my brake fluid isn't perfectly clean?

Regards,
Red

 

[Racer65]

Well I got a new Brake MC today. Thanks for the advice!

Now I am wondering if I should attempt to re-use my old proportion valve. It was full of gunk and has some nicks in the piston. I cleaned it up as best I can. The rubber is still reasonably pliable. I am guessing new seals don't exist.

That's why there is this solution.

 

[thebigredrocker]

Thanks Racer65 for the solution. What would one of your valves cost shipped to Washington State?

 

[Racer65]

It's $65 + $5 shipping. Here's a direct link to my site:
https://cityracerllc.shutterfly.com/pictures/24

You can also click on my Sig and scroll down. PM me if you decide to get one.

 

[Racer65]

Here's a review on Mud.

 

[Living in the Past]

It appears the master had leaked fluid down the booster.

I'm curious have you checked the booster out yet? Of the whole brake system that seems to be the hardest to deal with if it's bad. 76-80 used the same booster. OEM new ones have been NLA for a long time. Now kits to rebuilt them have dried up. There is a thread that's been around a while trying to find possible options. If you read thru the thread it outlines how to test the booster.

 

[sggoat]

My opinion is to purchase a new MC. No use in trying to rebuild a corroded MC and risking your life.

New master. Aisin still makes them(called Advics now)

 

[65swb45]

There is most certainly crud in the lines as well. The long term solution is to change everything in the hydraulic system, including the lines. Fortunately, they are now available in kit form. I bought a set from SOR last year to fix a customer's truck that someone had poured ATF into. I thought the price was reasonable, all things considered.

Best

Mark A.

 

[thebigredrocker]

I did pull the booster check valve and no fluid came out. I then pushed the booster rod in, held my thumb over the check valve hole, released the rod and after about 15 seconds I slowly lifted my thumb. It sucked air and made a fairly audible sucking sound, so it is holding some pressure. Not sure if they are supposed to hold pressure indefinately. So I figured I'd clean it up and replace it down the road if it's totally shot. Got the prop valve cleaned up, no clue if it will still function. Figure I'll get one of racer65's Valves if my rear brake lockup. Still a long ways off from a test drive. Hoping to see if my engine even runs in the next couple weeks. I appreciate all the good advice I've gotten here on MUD.

 

[thebigredrocker]

Also thanks for the brakeline advice, I have been comtemplating buying some from Rainman. Looks like his lines are good.