# Correct Brake Master Cylinder 1970



## aggie88 (Aug 13, 2005)

I need to replace my >20 year old master cylinder. It was changed in my high school days and was probably a Wagner repro. 

Anyone know the correct master cylinder type for a 70 with front discs? Is it the single longitudinal bail arm type or double F/R bail arms type? Pics would be great. Thanks!!!


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## lars (Sep 28, 2004)

1969 and 1970 master cylinders are the type with the dual wire clips: One clip covered the front reservoir area and the second covered the rear area. The master cylinder had rounded ends, and there was a rounded "hump" in the cover over each of the reservoir areas. In 1971, they switched over to the more rectangular master cylinder which uses a single longitudinal wire clip. 

The correct 69-70 master cylinder is not available, as far as I know. The 71-up style, which is interchangeable with the 69-70 other than its appearance, is available from Year One, NAPA, Ames, and other sources.


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## 05GTO (Oct 6, 2004)

Bendix Master Cylinders <--Click here and page down.


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## lars (Sep 28, 2004)

The single-clip master cylinder shown above is the replacement style offered. The dual-clip cylinder shown above is not the 69-70 disc brake MC - it's the standard-brake cylinder used from 67 thru 74. It is taller and narrower than the 69-70 disc brake MC, which is not available (the 69-70 disc brake MS is a big, fat, robust-looking MC with a much wider lid than the one pictured above).


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## BobG (Dec 20, 2006)

Hmmm .... interesting ... so they weren't COMPLETELY interchangeable with other A bodies ... I had a 70 skylark, with front discs, 350 2 bbl motor, TH400 and 2.73 rear end ... it had the single cap master cylinder for the brakes. I never noticed what my goat has ...


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## 05GTO (Oct 6, 2004)

I found some pictures on Ultimate GTO, 

http://ultimategto.com/1970/70_00030_5.jpg 

http://ultimategto.com/1970/70_00038_2.jpg

http://ultimategto.com/1970/70_00056_7.jpg

http://ultimategto.com/1970/70_00080_2.jpg

http://ultimategto.com/1970/70_00083_10.jpg

http://ultimategto.com/1970/70_00087_6.jpg

http://ultimategto.com/1970/70_00088_10.jpg

http://ultimategto.com/1970/70_00094_6.jpg

http://ultimategto.com/1970/70_00133_14.jpg

http://ultimategto.com/1970/70_00133_15.jpg

http://ultimategto.com/1970/70_00140_3.jpg


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## lars (Sep 28, 2004)

GM used several different master cylinders, even for same year production. They did not single-source the cylinders. The dual-clip disc brake master cylinder with the rounded shape that aggie88 refers to in his original post was only used in 1969 and early 1970. It looks similar to the 67-74 standard brake dual clip cylinder, but it's bigger and fatter. You can still buy the lids and the clips for the 69-70 dual clip disc brake master cylinders (see the Ames catalog), but you cannot buy the master cylinder itself. For all years, the single clip, rectangular master cylinder was also used with the disc brake cars. This is the only style cylinder used on disc brake cars from mid-70-up, and is pictured on most of the photos linked in 05's post above. The other styles shown above are the standard brake (non power) cylinders. You can buy the rectangular cylinders new, but to find one of the original dual-clip disc brake cylinders, you'll have to go junkyard shopping. You can install a single-clip cylinder on a 69-70, and it will still be "correct." But the dual clip versions are unique and pretty cool.

I've owned 2 GTOs with the dual clip disc brake MCs. One was a late-production 69 Judge, and the other was an early-production 70 Judge.


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## aggie88 (Aug 13, 2005)

This may not be the correct one, but will it fit a 70?
http://cgi.ebay.com/ebaymotors/ws/e...RK:MEWA:IT&viewitem=&item=190104187811&rd=1,1


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## lars (Sep 28, 2004)

That's the one.


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