[lemans-tom]

Hi all

Here’s one for all of you budding detectives who are looking for a mystery to solve.

I am looking for help identifying the following master cylinder. It’s on my 56 Chevy PU and I need to source a replacement but I do not know what it is from. It was fitted on to the truck in the US but the truck is now in the UK.
The running gear is a front clip and rear axle from a 1971 Chevelle.

Attached are some pics, I have more if needed. I have also taken some critical dimensions.

Mounting holes are spaced on 3.5 inch centre to centre. The inside is counter bored to two different dimensions - primary piston diameter is 36mm and outlet thread is ½ inch x 20 tpi, secondary is 24mm and 9/16 x 18 tpi.

It seems quite light for a master cylinder so I would guess its alloy of some sort rather than cast iron/steel. Cast numbers on the bottom read 442064 and stamped is 13 08 00 B (presume this is a manufacture date?)

Its mounted under the floor with a small vacuum brake booster.

Until I ID this my truck is immobile and blocking my drive, so any help gratefully received. Ask any questions you like if want further info.

Thanks
Tom

[speedydeedy]

I am sorry I can't I.D. it for you but it is aluminum. You could have it bored and re-sleeved in stainless steel then it would last very long and you would not have to hunt one down.

[poncho62]

If the reservoir is squarish looking from the top, I would say its an 80s Chevelle, Monte Carlo, S10 GM Master...........just a guess though.

[lemans-tom]

Thanks for the help so far.

I'll keep the good idea about a resleeve as my 'get out of jail' card (backup plan).

Poncho62 when you said squarish top did you mean like this (attached)?

Thanks

[grandpaws 57]

I agree with PONCHO 62 -looks GM 80ish

[poncho62]

yeah...with a black plastic snap on lid.....

[lemans-tom]

Black plastic snap on lid is right on the money, quite an air tight kind of fit for a push on design.

So if we are saying its an 80's GM m/c - are they generic across ranges eg truck, intermediate etc?

Thanks

[poncho62]

The 78-87 Monte Carlo, Lemans etc all seemed to use them as well as S10 pickups and Blazers......were pretty common.

[Triaged]

Originally Posted by lemans-tom

primary piston diameter is 36mm and outlet thread is ½ inch x 20 tpi, secondary is 24mm and 9/16 x 18 tpi.

An early S10 (say 87 like mine for example) with power brakes would be one one application for that MC. Manual brake MC's had a smaller primary piston.

http://www.napaonline.com/NOLPPSE/(S...+2014048+26270

Part: SS 4739571
Product Line: Safety Stop
Price : 84.99
Qty
Features & Benefits
Designed To Match O.E. Fit, Form & Function.; High Quality Rubber, Smooth Bore Finishes & Properly Threaded Outlet Ports Ensure Trouble-Free Operation.; Compatible w/ DOT Approved Silicone- Or Glycol-Based Brake Fluids.; Reservoir Fluid Level Switches Included Where Necessary.
Attributes
# of Line Ports : 2
Brake Master Cylinder Bore Size : 24 mm & 36 mm
Brake Master Cylinder Line Thread Size : (1) 9/16" - 18 & (1) 1/2 - 20
Warranty
24 Months or 24,000 Miles Whichever Occurs First

Warranty PDF
">Warranty Detail
Material Safety Data Sheet (MSDS)
There is no MSDS for this item
Application Information: 1987 Chevrolet Truck S10 - Pickup
Comments: w/ Power Brakes
Per Car Qty: 1

[lemans-tom]

That's great, many thanks to all of you who responded, I'm off shopping................................