brakes leaking from proportioning control valve

Barts_65 · 01-30-2003, 07:04 PM

The brake lines or proportioning valve components on my '69 mach1 are leaking severely. I have attached a link(see below) to a photo of the parts involved. the lines look intact. Can anyone tell me what they might think the leak is coming from. also, if there is a source for these parts new.

Also,can anyone tell me what the 3" brass part under the actual proportioning valve is? The part number is c90a-2b091-a. There seems to be 2 small factory holes on the inside where the thin black recessed band is.

Thanks for the help.

Bart

Kisner · 01-30-2003, 09:53 PM

The 3" brass cylinder is your proportioning valve. The other part (where the master cylinder and proportioning valve hook into) is your brake fluid distribution box and brake warning switch. Technically, I believe it's called a pressure differential valve. Believe you can get 1 or both from Mustangs Unlimited or National Parts Depot. If not, you might be able to get an original used one from Metro Mustang. Not sure where the leak could be coming from other than a bad flared end on one of the lines or possibly loose connection. If they're a hair loose, I know from experience fluid will run out. Can you see fluid running out when someone else presses the brakes down? Also, is any fluid coming out of the brake warning switch? I believe there's 3 rubber seals in the fluid distribution box. If one's gone bad, I'm not sure, but it could be forcing fluid out the connection.

Barts_65 · 02-01-2003, 12:36 AM

Kisner, thanks for the excellent info. I checked a little closer for the leak and determined that it is coming out of two small factory holes in the side of the proportioning valve. Do you know what the deal is on that and if theye are rebuilable. The reason i am asking is because I checked all the sources and the proportioning valve is a very hard item to get. the block is available.

Thanks again.

Kisner · 02-02-2003, 02:58 PM

Wish I could help you, but I don't what the 2 small holes are for. Not sure if it's rebuildable or not. I'd suspect a rubber seal has gone bad on the inside but even if you could take it apart might be hard to find the right size seal to replace it. If you haven't already, try Metro Mustang for an original used one. They have countless stangs they're continually parting out. The guy I always deal with is Tim. His e-mail is tim@metromustang.com or you can call him at 404-767-3378. During my restoration process, he had several items I couldn't buy anywhere else.

01-30-2003, 07:04 PM	#1
Barts_65 Registered Member Join Date: Sep 2001 Location: Islip, NY. 11751 Posts: 19	brakes leaking from proportioning control valve The brake lines or proportioning valve components on my '69 mach1 are leaking severely. I have attached a link(see below) to a photo of the parts involved. the lines look intact. Can anyone tell me what they might think the leak is coming from. also, if there is a source for these parts new. Also,can anyone tell me what the 3" brass part under the actual proportioning valve is? The part number is c90a-2b091-a. There seems to be 2 small factory holes on the inside where the thin black recessed band is. Thanks for the help. Bart __________________ Thanks and Happy Mustang Motoring. Bart 1969 Mach 1, 1965 C-Code Coupe and 1966 T-Code daily driver

02-01-2003, 12:36 AM	#3
Barts_65 Registered Member Join Date: Sep 2001 Location: Islip, NY. 11751 Posts: 19	proportioning valve Kisner, thanks for the excellent info. I checked a little closer for the leak and determined that it is coming out of two small factory holes in the side of the proportioning valve. Do you know what the deal is on that and if theye are rebuilable. The reason i am asking is because I checked all the sources and the proportioning valve is a very hard item to get. the block is available. Thanks again. __________________ Thanks and Happy Mustang Motoring. Bart 1969 Mach 1, 1965 C-Code Coupe and 1966 T-Code daily driver

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01-30-2003, 09:53 PM	#2
Kisner Registered Member Join Date: Nov 2000 Posts: 290	The 3" brass cylinder is your proportioning valve. The other part (where the master cylinder and proportioning valve hook into) is your brake fluid distribution box and brake warning switch. Technically, I believe it's called a pressure differential valve. Believe you can get 1 or both from Mustangs Unlimited or National Parts Depot. If not, you might be able to get an original used one from Metro Mustang. Not sure where the leak could be coming from other than a bad flared end on one of the lines or possibly loose connection. If they're a hair loose, I know from experience fluid will run out. Can you see fluid running out when someone else presses the brakes down? Also, is any fluid coming out of the brake warning switch? I believe there's 3 rubber seals in the fluid distribution box. If one's gone bad, I'm not sure, but it could be forcing fluid out the connection.

02-02-2003, 02:58 PM	#4
Kisner Registered Member Join Date: Nov 2000 Posts: 290	Wish I could help you, but I don't what the 2 small holes are for. Not sure if it's rebuildable or not. I'd suspect a rubber seal has gone bad on the inside but even if you could take it apart might be hard to find the right size seal to replace it. If you haven't already, try Metro Mustang for an original used one. They have countless stangs they're continually parting out. The guy I always deal with is Tim. His e-mail is tim@metromustang.com or you can call him at 404-767-3378. During my restoration process, he had several items I couldn't buy anywhere else.