How to fix master cylinder leak

[Jalbao]

Every time I press the brake pedal, some brake fluid leaks from where the master cylinder connects to the brake booster.

The attached pictures shows the location where the leak occurs (at the red arrow).

I've confirmed that the master cylinder is tightened.

What can cause this leak to occur and what can I do to fix it?

 

[DAD2SIX]

Bad seal in the master cylinder. Either rebuild or replace the master cylinder.

 

[45Kevin]

Probably on eof the seals in the plunger assembly inside the MC.

Get a rebuilt kit. http://www.sor.com/sor/cat014.tam?c...57324865&pagenumber.ptx=1&page.ctx=cat014.tam

Check with other vendors also on this site for the rebuild kit. Prices may be better. I got OEM from CDan IIRC at a competitive price.

 

[Jalbao]

thanks for the information.

NAPA sells an aftermarket for 40 bucks. should I stay away from the aftermarket ?

 

[Fast Eddy]

IMO, if you're going to spend the time to rebuild it, get the OEM parts. They will have better quality seals.

 

[45Kevin]

thanks for the information.

NAPA sells an aftermarket for 40 bucks. should I stay away from the aftermarket ?

Did you get a quote from CDan at American Toyota? He has really good pricing.

I use aftermarket parts sometimes. In Fact, some aftermarket parts are the same as OEM parts, just a different package.

 

[Jalbao]

Did you get a quote from CDan at American Toyota?

No, I haven't. I went ahead and bought the $40 NAPA master cylinder.

Part Number: NMC P2273
Product Line: Proformer Master Cylinders

 

[hatman406080]

got my from cruiser corps. and you need a gasket too

 

[Jalbao]

What gasket are you referring to?

 

[Caddisfly]

What gasket are you referring to?

X2

I bought an OEM master a couple of years ago. The rear reservoir gradually loses fluid over time, but there are no leaks in any of the lines. I did not install any kind of gasket, so maybe I missed one step in the process.

 

[hatman406080]

between master C. and brakebooster

 

[Jalbao]

between master C. and brakebooster

Thanks for the headsup on that gasket. Not only did I not have one originally, but I overlooked it on the parts list.

I'm starting to think that I didn't need a new m/c, but rather a new gasket.


For the record - the gasket here in this '72 FJ40 parts list is listed as 47275.

 

[Caddisfly]

Thank you. I'll order one from cruisercorps right now.

<edit> According to the parts diagram I just looked at on the SOR site, the '78 master does not use a gasket. Early models do, and late models do, however.

Pighead, do you have any insight as to why the rear reservoir on an OEM master (with less than 1,000 miles of use) might be leaking?

 

[Pighead]

I'm starting to think that I didn't need a new m/c, but rather a new gasket.

Disagree. You should not have brake fluid near that gasket.

 

[SouthBostonFJ40]

You can order a new Aisin FJ80 master from Rockauto.com for about $65 that will fix your problems.