The Stovebolt Site Forums The Parking Lot Big Bolts I give up on a master cylinder

Can someone please give me the part number and the place to find a NEW master cyl.

I want to replace the old leaking one.

It's for a 2 ton 6500 viking.

Later I will redo ALL brakes, and next winter repair the hydrovac.

I have searched ebay, and everywhere, but NOTHING when it comes to 2 ton trucks.

HELP PLEASE

Hy lastchancetowing, Raybestos p/n MC21698 $126.79 U.S.D. at Rock Auto, hope that helps.

Ulf,

I believe the MC that 3B is talking about is for the 1/2 ton trucks with a 1-1/8" bore.

Your truck could have a 1-1/4" bore (Model 361-S)(casting number 5454517) part number 5454494 or it could have the Heavy Duty 1-1/2" bore (Model 371-B) (casting number 5454781) part number 5454774.

I have never been able to find a source for "new" MC's for our big TF trucks. The last two time I needed one I came up empty and I had my existing MC sleeved and had a new kit installed.

I use Joe Way at Serria Specilty Automotive.

Mike B

Hy Mike B, Raybestos p/n MC21698 is a 1 1/4" bore master cylinder, and is listed as the correct master cylinder for this truck

Contact Geoff at, Alretta Truck Parts. Phone (508)788-9409

Thanks all... I have some things to choose from now.

Or I just have to find a convert to firewall mount kit.

But I don't want that, want the engine compartment as is.

Got a very nice mail from Geoff at Alretta.
He asked me for some info, and stated, he had everything for these old trucks...



Ulf-
Yes, I can help a guy from Sweden!

but you need to help me to confirm what you've got...

A picture of the master cylinder, a casting number off the side or bottom? Do you know wheel brake sizes, gross vehicle weight rating? As we assemble data, all the answers fall into place for you to get the correct parts.

I have shipped extensively to Europe, so not to worry that you are a land too far...

I should be able to supply a master cylinder assembly, and probably also the hydrovac, any wheel cylinders, the hub seals or bearings, brake hoses, and maybe some additional items. This is my area of expertise.

As for a kit, the industry as a whole is discontinuing them for some time now, and in any event, if the bore has porosity, then the kit will not seal anyway. I always believe in the sanctity of a new cylinder!

So snap me a couple of clear shots, on or off the vehicle, and get me a casting number if possible, as well the build data for brake sizes at the wheel (shoe width x diameter of the drum across the shoes).

I think I shall surprise you with what is possible!

Happy Easter,


Yours,


Geoff Rosenberg

Sent from my iPad -
Geoffrey Rosenberg
President
Alretta Truck Parts Inc.
http://www.Alretta.com

3B,

Thanks for setting me straight...

Mike B

The only time you need a stock single system mastercylinder in any old chev or GM truck is if it is sitting in a museum. No I don't want to see any extra holes drilled or parts cut, but a newer style dual mastercylinder will fit under there, its just a bit harder to fill it. For saftey you don't want a single system, if you develope a leak, your toast.

What I will do, is geive him the cast number.
Same time I will ask him if there is a dual chamber that will fit my truck.

But I think that if I get a dual I can only connect the hydrovac to one circuit, front or rear.

If I could choose I would like to have a new master, dual, PLUS, vacuum brake booster... ( not steering pump driven ) that fits under the truck, and still can feed the big wheel cylinders and drums ...

But I haven't found any. All I see is small cylinder, and small booster.

If someone can specify for a 2-ton, a dual master and booster combo that would work, I would buy it the same second !!

I planned on getting it on the road only with a fast fix, new master only, and fix all brakes next winter. New brake lines, hoses, and cylinders and all....

Removed the master cylinder.

http://i185.photobucket.com/albums/x264/uffeg/viking%20brakes/20110424189.jpg

A lot of fluid in the rubber cap !!

Indeed the 1 1/4" dia bore cylinder.

http://i185.photobucket.com/albums/x264/uffeg/viking%20brakes/20110424188.jpg

The piston is a bit more then 2 1/4 inch, 58mm long.

http://i185.photobucket.com/albums/x264/uffeg/viking%20brakes/20110424184.jpg

http://i185.photobucket.com/albums/x264/uffeg/viking%20brakes/20110424186.jpg

Casting of the master is 5454517.

The bottom of the master i pitted a lot in the bottom.

I think it is too much to be fixed...

Geoffrey at Alretta truck parts had new master cyl. And factory remanufactored hydrovacs !!

So I will buy both.... from them...

He had rear and front wheel cyls and all...

Thanks for the tip Spanky !!

The bennefit to having a new master is you'll be putting full pressure to the rest of the system.
The disadvantage to having a new master is you'll be putting full pressure to the rest of the system.

What I mean is that all of the rest of your componenets may be borderline now, and being able to push harder may just blow one out. This is where you come into the territory where a dual circut is safer than a single, something as simple as a torn cup in one of the wheels slaves will be all it takes. Wether you keep it stock or convert it, it's best to collect all your parts and do the whole system at once.
Dual circut is safere, no doubt, but there's also the fact that most of these beasts have been on the road for decades with a single circut, properly maintained they will be on the road for decades more.

I will buy new brakelines, and wheel cylinders, and hoses, all for next winter.

Will only drive a couple of kilometers max this summer.

Very carefully...

also, consider that if you change anything on that braking system from the original design, then crash thru your neighbors house...your insurance COULD refuse to cover it.

Unless the steering goes out at the same time, one should be able to avoid a house.
Better not work on the steering system, throttle, drive line, body or anything else for that matter. A fender or steering linkage may fall off harming someone, if the drive shaft fails it could project a part and hit an innocent bystander, if the throttle sticks, if the tailgate falls off, if the bumper should fall off, or the door handle, etc. etc. etc. I guess the only way is to hire a bonded and insured mechanic shop to work on anything so the burden goes to them.

Anyone know of an easy upgrade to a dual circuit master on a'46 ton-and-a-half?

Motoswiz - I'm an insurance agent and have never seen any exclusion like you mentioned.

Still looking for a dual circuit master for a 46 1.5 ton. Anybody here made that switch? I absolutely agree that the single pots are major hazard.