The MGA With An Attitude
MASTER CYLINDER REBUILD KIT has Wrong Front Seal -- FT-021

REVISION: The seal is apparently correct for OEM application. Mr. Buscaglia seems to have a non-original rebuild type piston in his master cylinder. See addendum below for some possible piston variations you might encounter.

At 03:35 PM 8/28/04 -0400, Tony Buscaglia wrote:
"The first seal in the kit, that fits over the end of the piston, were too large for the piston that was in my MC."

This is for Moss Motors part number 180-970 Rebuild Kit for the 7/8" bore dual master cylinder, MGA, Sprite/Midget (not 1098cc), TR2-4A. Problem is that the front main cup (with the donut hole) is too wide. Groove in the spool is 1/4" wide and the center hub of the cup seal is 3/8" wide, so the cup seal doesn't fit on the spool.

Two different selas for master cylinder pistons

At 08:54 PM 8/29/04 -0400, Tony Buscaglia wrote:
>"I found that Northwest Import also sells Lockheed/Delphi rebuild kits. The number on theirs is LK71527 as opposed to the number on the boxes I received from Moss that are LK11527. I wonder if NW has the correct kits."

Moss Motors was notified on August 29, 2004.

ADDENDUM - Oct 4, 2004:

Moss recearch into this situation reveals that their seal kits DO contain the correct seal for the MGA OEM assembly. For the past 10 years Moss has been supplying AP Lockheed (now Delpho-Lockheed) master cylinders and rebuild kits, the design has not changed and is still the same as OEM. Moss has been getting only about two returns per year noted "not correct for application".

The picture above shows a different piston, apparently some aftermarket part, probably installed during a past rebuild. Some time ago Roadstar-Nelson, and Beck Arnley used to sell rebuilt master cylinders for this application which contained non-OE type pistons and seals with the narrower groove and seal as shown in the picture at the top of this page. Today rebuilders may opt to replace these non-OE pistons with original type parts, so the original type seals can be used.

Notice: Illustrations in the "MGA Workshop Manual" and the "MGA Service Parts List" may not look exactly like the original spec piston (but they are close).

See figure at right. The aftermarket type piston has all ridges with about the same OD, and the narrower seal fits between the first two ridges. The OE type piston has a smaller ridge a little distance in from the end, and the wider EO seal fits over that ridge.

Moss Motors has noted their intention to post an illustration in the next printing of their MGA parts catalog to call attention to this variation in some aftermarket pistons and seals.

Before you ask, no, I do not know where you can buy original type pistons. Apparently some rebuilders make their own original type pistons for replacements during restoration services.

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