Diagnosing issue with my clutch master cylinder (1 Viewer)

[mountainpapi23]

Brake fluid has been leaking from the where my clutch master cylinder is bolted to the clutch booster. I pulled off the master cylinder expecting to see a failed gasket of some sort but it doesn't seem like there is any gasket at all where they join together. Then it occurred to me that brake fluid should be contained with in the the master cylinder shouldn't it? Leading me to think that a seal has failed inside of the cylinder allowing brake fluid out of unsealed junction between the master cylinder and the booster. Is this correct? Here are some pictures if anyone who knows more than I do (which is anything at all) and can tell what is wrong. Any help is appreciated.

 

[jblueridge]

You are right; all fluid be contained within the master.
The leak has eaten the paint off the booster… clean the booster with brake cleaner spray.
The master can be rebuilt with new rubber parts but a new one may be available too.
What vehicle is it?

 

[mountainpapi23]

You are right; all fluid be contained within the master.
The leak has eaten the paint off the booster… clean the booster with brake cleaner spray.
The master can be rebuilt with new rubber parts but a new one may be available too.
What vehicle is it?

Now should I be worried about brake fluid that has gotten inside of the booster?

 

[mountainpapi23]

Now should I be worried about brake fluid that has gotten inside of the booster?

It is a 1994 Toyota Dyna Fire Truck

 

[mountainpapi23]

Now should I be worried about brake fluid that has gotten inside of the booster?

It is a 1994 Toyota Dyna Fire truck

 

[jblueridge]

I’d buy some electronics cleaning spray and hose down the booster parts that got soaked with brake fluid.
Safe for plastics.
crc

Hmmmmm, I don’t know about replacement parts.
Any numbers printed, cast or stamped on the master or the booster?

You are West Coast?
I am in VA and I used these folks for rebuilds of brake hydraulics.
Not cheap but a lifetime guarantee.
They like to rebuild the booster and master both.
whitepost

Duncan Imports seems to be owned by a guy who has his own JDM firetruck fleet.
Duncan

If you know which Dyna model you have you can use.
amayama
or
jpcarparts. jpcarparts has actual people who read messages and questions you send their way.

 

[mountainpapi23]

I’d buy some electronics cleaning spray and hose down the booster parts that got soaked with brake fluid.
Safe for plastics.
crc

Hmmmmm, I don’t know about replacement parts.
Any numbers printed, cast or stamped on the master or the booster?

You are West Coast?
I am in VA and I used these folks for rebuilds of brake hydraulics.
Not cheap but a lifetime guarantee.
They like to rebuild the booster and master both.
whitepost

Duncan Imports seems to be owned by a guy who has his own JDM firetruck fleet.
Duncan

If you know which Dyna model you have you can use.
amayama
or
jpcarparts. jpcarparts has actual people who read messages and questions you send their way.

I am in Northern California. Thanks for the help.

 

[ToyotaDyna]

Hi there,

It would be best to change the whole master cylinder for a new one, more than likely the bore is pitted and has torn the last seal.

If you open the cylinder and just put a kit in, it will fail again in the near future.

Open it up have have a look at the bore inside anyway.

Sometimes there a small seperating bolt in the side if its a dual cylinder, just release the tension a bit by pushing the plunger in and remove the bolt and be very careful re installing it not to damage the plunger.

Put your frame number into toyodiy and find your master cylinder.

Toyota in the US can order one for you and even a cheaper non Toyota version if you wish.

If stuck, I can get one for you.

ToyotaDyna

----

Looking for a LHD, Diesel, Land Cruiser?

Canarian Land Cruiser Exports • DIESEL • LHD

 

[ToyotaDyna]

This should be your one. Just check your VIN and frame.

ToyoDIY.com

ToyotaDyna

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Looking for a LHD, Diesel, Landcruiser?

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[roscoFJ73]

It is a 1994 Toyota Dyna Fire Truck

There is about 31 models in that year. The master cylinder (brake and clutch) are measured in 1/8ths of an inch across the bore. Yours, if its a B engine, is probably a 5/8ths inch bore. This part number is for a BU73 1994 31401-36050, but dont count on it until you know the exact model.

 

[roscoFJ73]

This should be your one. Just check your VIN and frame

He is after a clutch MC , thats for a brake MC

 

[ToyotaDyna]

Thanks roscoFJ73, I'm too used to the non Boosted clutches in the older Dynas

 

[mountainpapi23]

This should be your one. Just check your VIN and frame.

ToyoDIY.com

ToyotaDyna

-----

Looking for a LHD, Diesel, Landcruiser?

Canarian LandCruiser Exports • LHD • DIESEL

that's my frame number U-BU73-MDPDT4

 

[mountainpapi23]

There is about 31 models in that year. The master cylinder (brake and clutch) are measured in 1/8ths of an inch across the bore. Yours, if its a B engine, is probably a 5/8ths inch bore. This part number is for a BU73 1994 31401-36050, but dont count on it until you know the exact model.

View attachment 2726737

yeah this cylinder is 5/8s. Thank you.

 

[mountainpapi23]

that's my frame number U-BU73-MDPDT4

Hi there,

It would be best to change the whole master cylinder for a new one, more than likely the bore is pitted and has torn the last seal.

If you open the cylinder and just put a kit in, it will fail again in the near future.

Open it up have have a look at the bore inside anyway.

Sometimes there a small seperating bolt in the side if its a dual cylinder, just release the tension a bit by pushing the plunger in and remove the bolt and be very careful re installing it not to damage the plunger.

Put your frame number into toyodiy and find your master cylinder.

Toyota in the US can order one for you and even a cheaper non Toyota version if you wish.

If stuck, I can get one for you.

ToyotaDyna

----

Looking for a LHD, Diesel, Land Cruiser?

Canarian LandCruiser Exports • LHD • DIESEL

Hi there,

It would be best to change the whole master cylinder for a new one, more than likely the bore is pitted and has torn the last seal.

If you open the cylinder and just put a kit in, it will fail again in the near future.

Open it up have have a look at the bore inside anyway.

Sometimes there a small seperating bolt in the side if its a dual cylinder, just release the tension a bit by pushing the plunger in and remove the bolt and be very careful re installing it not to damage the plunger.

Put your frame number into toyodiy and find your master cylinder.

Toyota in the US can order one for you and even a cheaper non Toyota version if you wish.

If stuck, I can get one for you.

ToyotaDyna

----

Looking for a LHD, Diesel, Land Cruiser?

Canarian LandCruiser Exports • LHD • DIESEL

I have found the part using the exact part number 31401-36050 in Megazip. With the same search In Amayama it pops up with a slightly different part number 31401-36052. It says it's toyota genuine and its significantly cheaper. Would you advise spending the money for the exact part number? or is it common for slightly different part numbers to refer to the same part.

 

[ToyotaDyna]

I have found the part using the exact part number 31401-36050 in Megazip. With the same search In Amayama it pops up with a slightly different part number 31401-36052. It says it's toyota genuine and its significantly cheaper. Would you advise spending the money for the exact part number? or is it common for slightly different part numbers to refer to the same part.

I had the same issue with my BJ40 ( for the brake master cylinder though ) at the time I bought the rebulit kit, it only lasted a few months.

For this reason I bought the whole unit, Toyota genuine cheaper version.

That was 5 years ago and its hasn't given any problems yet.

Now I make sure to flush the brake fluid ( and clutch fluid ) yearly to stop moisture buildup ( the po never did it )

The original would be nice but the other will be fine too.

Each non original part manufacturer, in my experiance, will have their own slightly different part number for the same Toyota original part.

ToyotaDyna

------

Looking for a LHD, Diesel Land Cruiser?

Canarian Land Cruiser Exports • DIESEL • LHD

 

[roscoFJ73]

or is it common for slightly different part numbers to refer to the same part.

Yes, but .
There are 5-6 companies like Amayama, maybe compare their prices. You might get the proper part number at a better price.

 

[hugemanatee]

if you just want to rebuild it quick and dirty to get moving again run a bit of green scotchbrite - like a half inch strip three inches longish, take that and twist it around a drill bit or nail or something in your cordless drill. take the guts out of the master, run that scotchbrite combo in there easy-like, just slow rpm and in&out like you're honing a tiny cylinder, lube is your friend.

I've done this on lots of bikes and cars and trucks, sometimes the rubber cups on the plunger are so torn that this won't help, but often times it's just not making a good seal and the rubber isn't damaged too badly.

YMMV, get a rebuild kit soon if the cups are shot.

PS

soooooper jealous of your firetruck, I'm looking seriously at a DYNA LY151 firetruck (lightweight, six lug, 3L engine, 4x4)

cheers!