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MGA brake master cylinder

Moss Motors
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mgbgtn tom newman
Campbell River, BC, Canada   CAN
I was looking to replace my master cylinder but Moss lists a different one for drum brake ( 1500 & early 1600) and disc brake cars and I wondered what the difference was other than the lid. I was wondering because I am using MGB disc brakes.

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Tbird Avatar
Tbird ET Taylor
Land O Sky, NC, USA   USA
I just checked the Moss web site.

Looks to me like they list 2 different units for the 1500 with the standard top ...
180-670 (TRW)
180-672 (AP)
and 2 different units for the 1600 with the extended top...
180-752 (TRW)
180-753 (AP)

All with 7/8 bore.

Since you have MGB brakes I'd use one of the M/C's for the 1600 but I'm guessing you already have the extended top that you can transfer. In that case it shouldn't matter - all 7/8 bore.

If using the TRW you might want to ask about this info
https://mgaguru.com/mgtech/brakes/bt101a.htm



Edited 1 time(s). Last edit at 2019-02-05 06:44 PM by Tbird.

ghnl Avatar
ghnl Silver Member Eric Russell
Mebane, NC, USA   USA
1961 MG MGA "Calvin"
In reply to # 3886639 by mgbgtn Moss lists a different one for drum brake ( 1500 & early 1600) and disc brake cars...

That is not correct. All MGA 1600's had disc brakes. (not talking about the Twin Cam or Deluxe with Dunlop four wheel disc brakes - MGA's with Dunlop disc brakes use a different master cylinder.)

The 1500's & 1600's master cylinders are the same - it is only the lids that are different (larger for the MGA with Lockheed disc brakes).

Quote: I was wondering because I am using MGB disc brakes.

I have MGB brake calipers in my MGA. I use the MGA master cylinder with the larger disc brake cover.



Eric Russell ~ Mebane, NC
1961 MGA #61, 1981 Alfa Romeo GTV6, 1984 Alfa Romeo Spider, 1991 Honda ST1100



Edited 2 time(s). Last edit at 2019-02-05 06:58 PM by ghnl.

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2mgs4doors Avatar
2mgs4doors Harry Rathvon
Lancaster, PA, USA   USA
The only difference from 1500 to 1600 was the high top for more fluid capacity for the disc brakes

Pawtucket, RI, USA   USA
Dear Tom,

Yes, to set you straight, there are only 2 master cylinders for the MGA 1500 & 1600 models (excluding the Twin Cam & 1600Mk2 Deluxe with all round Dunlop disc brakes.)
The 1500 & 1600 brake master cyls are identical , both 7/8" bore with the exception of the lid.
1500 drum brake cars had a flat lid, 1600 models had a raised aluminum lid to accommodate more fluid for the disc brakes.

HOWEVER, the 1500 cars had a flatter engine hood, whereas the 1600 and Twin Cams had a more curved engine hood to accommodate both the raised brake master cylinder and the height of the Twin Cam engine.
I think if you fit the 1600 raised master cyl, it may be a very tight fit and possibly touch the top of the 1500 flatter hood. (Not sure,so others can chime in here). The 1500 & 1600 style engine hoods are interchangeable.

Also, the only issue with fitting disc brakes (MGA or MGB) is if you do stick with the 1500 flat cylinder, you have to make sure you keep the brake fluid level in the cylinder topped up all the time.

Cecelia
SCARBOROUGH FAIRE

59mgaguy Avatar
59mgaguy John Terschak
Wakeman, OH, USA   USA
1930 Ford Model A "Jenny"
1959 MG 14/28 "Jessie"
1974 MG MGB "Oooops"
Tom,

SF has one of the best Master cylinder and the price is right. I know I picked one up from Cecelia at GT. I really couldn't beat the price she gave me and I needed it at the time. So I made out.

GT about the only time Cecelia and I can get together for a informal talk. Not only doe she know the MG but she's a Hoot.



This was a paid commercial broadcast. (need another good deal next time at GT Cecelia)

John

Pawtucket, RI, USA   USA
Dear Tom,

Why do you want a new master cylinder, what's wrong with yours if anything? other than it could be the original one.
I always say 'brakes are your life!'

As John said previously, he purchased one of our newly produced brake master cylinders at the NAMGAR GT, these are made from our own exclusive new tooling, we have sold over 1000 units, and are identical to the original LOCKHEED ones, except they don't have the LOCKHEED name cast into the side of the unit.

We opted to produce these due to safety issues we had with previous new TRW ones we had gotten.
Ours even come with the original style metal cap.

If need be, they can be rebuilt in the future with any of the original or aftermarket rubber seal kits.
And the best thing about them is they are only $67.95 for the 1500 flat style..
We also reproduced the 1600 one with raised lid reservoir, maybe that's all you really need.

Cecelia

ghnl Avatar
ghnl Silver Member Eric Russell
Mebane, NC, USA   USA
1961 MG MGA "Calvin"
In reply to # 3886769 by Cecelia Bruce ...the 1500 cars had a flatter engine hood, whereas the 1600 and Twin Cams had a more curved engine hood to accommodate both the raised brake master cylinder and the height of the Twin Cam engine.

I think if you fit the 1600 raised master cyl, it may be a very tight fit and possibly touch the top of the 1500 flatter hood. (Not sure,so others can chime in here). The 1500 & 1600 style engine hoods are interchangeable.

Interesting observation. I know the hood (bonnet) was changed but my understanding is the hood (bonnet) surround did not change. The master cylinder is so close to the surround - actually partially underneath it - that I do not think the different hood (bonnet) would be a factor. Also, the additional bulge of the later hood (bonnet) is all in the front half.

http://mgaguru.com/mgtech/body/bd121.htm



Eric Russell ~ Mebane, NC
1961 MGA #61, 1981 Alfa Romeo GTV6, 1984 Alfa Romeo Spider, 1991 Honda ST1100

mgbgtn tom newman
Campbell River, BC, Canada   CAN
Thanks for the information. The reason for the new master is that the old one is rusty in the bores and not serviceable.

59mgaguy Avatar
59mgaguy John Terschak
Wakeman, OH, USA   USA
1930 Ford Model A "Jenny"
1959 MG 14/28 "Jessie"
1974 MG MGB "Oooops"
Tom,

Bit of advice...Don't throw it away.


John

Graham MV Graham Martin
London, london, UK   GBR
Dont know what its like your side of the pond, but I found the TRW only works with drum brakes. With disc brakes the pads didnt return properly after braking, leaving the brakes seized on. With drum brakes, there are springs to release the shoes. But the AP worked fine.
Just my personal experience and you will find much written up on Barney's website about it. He gives the solution if you have the discs pads locking but I wasn't confident enough to make adjustments to the master cylinder so changed to the AP

Rob Z Avatar
Rob Z Silver Member Rob Zucca
Camarillo, CA, USA   USA
1960 MG MGA
I did have to drill my relief valve because of dragging brakes after fitting the TRW master. The relief hole worked, but I shouldn’t have had to do that.



"Time flies like an arrow......Fruit flies like a banana"

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