Time for a new master cylinder?

Applied the brakes yesterday and the pedal went slowly to the floor. Did have some limited breaking action, but no where near normal.

Tried to pump them up but with little success. Master cylinder is full of fluid, so I'm thinking the seals on the piston might have given up the ghost.
I'm no expert on brakes though, so what say you. Any advice is much appreciated.

Its my daily driver but I have access to my sons car so I'm not in a great rush, but I still need to get it fixed ASAP.

Thank you for the help.

G57

If you're certain there's no fluid leak, the MC is a logical place to start.

You can also get O/H kits for them, if you're inclined to rebuild rather than replace.

If you decide to replace, the SVO came with an aluminum body while most of the Lincolns came with cast iron units. SVO aluminum is lighter and correct.

NOTE: The aluminum cylinder bore is hard anodized and MUST NOT be honed. If there's scratches in the bore, it must be replaced.

Mike,

I don't mind rebuilding it, and would like to keep my aluminum original. I just need to know what kit to get. Do you know of a current part number to order so I know I'm getting the correct kit? I can't just run down to the parts store and return it.

Thanks for the help.

Repair kit:
RAYBESTOS MK1617 {#TM351617} Professional Grade Info
$17.85 on rockauto.com

FORD	MUSTANG	1984-1986
LINCOLN	CONTINENTAL	1982-1984
LINCOLN	MARK VII	1984

It's a 1.25" bore, btw.

Quote:

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Originally Posted by MikeFleming

You can also get O/H kits for them, if you're inclined to rebuild rather than replace.

If you decide to replace, the SVO came with an aluminum body while most of the Lincolns came with cast iron units. SVO aluminum is lighter and correct.

NOTE: The aluminum cylinder bore is hard anodized and MUST NOT be honed. If there's scratches in the bore, it must be replaced.

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Just curious, could it be sleeved?

Quote:

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Originally Posted by rodster

Just curious, could it be sleeved?

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Probably but reman MCs are $51-95/US. Sleeving & associated machining would probably cost more.

Mike,

Thank you for the parts information.

I figured while I had break fluid dripping I might as well overhaul the proportioning valve while I was at it. Ordered rebuild kit from Muscle Car Research LLC.

Anybody ever use it before? Any tricks or tech tips to make the job easier?

I'll let you all know how it goes after I'm done.

G57

Quote:

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... I might as well overhaul the proportioning valve while I was at it. Ordered rebuild kit from Muscle Car Research LLC.

Anybody ever use it before? Any tricks or tech tips to make the job easier?

---

I wasn't aware anyone had kits for the SVO prop valve. Mark Haas had kits a couple years back though. The spring rate in the SVO PV is different from the other FOX Mustangs but I suppose a GT spring might be close enough.

The issue I've seen with O/Ring PVs is getting out the old, dried, brake fluid (aka hard crud) to allow disassembly. The PV blocks are hard anodized aluminum - be sure not to use an aluminum-eating caustic cleaning material. No wire brushes - only soft fiber. Most cleaning stuff will damage the viton/rubber/neoprene seals so they will need to be replaced.

It's not a complicated device at all. Remove the fail indicator switch on the top, pull the rear plug cap (uses aluminum or copper sealing washer), pull the spring and plston out, etc. Perhaps the most difficult part will be repairing the SAE comes for the hydraulic lines to seal to. Search for Fleming Famous Sealing Washers.

And scrupulous cleaning of the assorted ports/passages. Somewhere in a box I have a used, original SVO PV that needs cleaning and refurb'ing.

Mike,

This is the kit I bought. Says its good for the SVO.



1977 - 1986 Ford/Mercury Brake Pressure Control Valve Kit

SKU: 2B257-Kit-7
Price: $12.00
Quantity *




https://www.musclecarresearch.com/si...?itok=BaTLq_Hd

A Muscle Car Research Exclusive!

Muscle Car Research is proud to offer a rebuild kit for the following Ford and Mercury brake pressure control valves:

• D7EA-2B328-AA (service part number unknown)
• D9EC-2B328-AB (service part number and applications unknown)
• E0ZC-2B328-AA (service part number E0ZZ-2B257-A)
• E3SC-2B328-BA (service part number E3SZ-2B257-B)
• E4ZX-2B328-AA (service part number E4ZZ-2B257-A)

Our kit contains all of the internal o-rings and seals needed to rebuild your leaky valve and return it to "like new" operating condition.
The contents of the kit can be seen in the picture above. All of the rubber parts are molded from a 70 durometer ethylene propylene diene monomer (EPDM) rubber compound that is fully compatible with automobile brake fluid. All parts are made right here in the USA!
Are you unsure if this kit is for you? original applications include the following vehicles:
D7EA-2B328-AA

• 1977 - 1978 Ford Mustang

E0ZC-2B328-AA:

• 1980 - 1986 Ford Mustangs (excluding SVO) and Mercury Capris
• 1980 Ford Fairmont and Mercury Zephyr

E3SC-2B328-BA

• 1986 Ford Thunderbird

E4ZX-2B328-AA:

• 1984 - 1986 Ford Mustang SVO

I do believe thats the kit Mark Haas put together as I ordered 2 of them. One to put in the car and one as a spare.

Mike Is that 1.25" bore OR 1.125" bore. I see the kits list as an 1-1/8 bore (=1.125")

1.125", aka -1/8" bore.