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Help needed identifying the correct master cylinder
Hi All,
Got my 78 F-250 Supercab six months ago and the breaks were going all the way to the floor and I think I have it narrowed down as being the master cylinder. I bought a new master cylinder, bench bled it, went to put it on and the brake lines were on the opposite side from the old master cylinder. The old master cylinder had the brake lines coming into the right side of the master cylinder, when the master cylinder was installed on the truck. I could move the brake lines, but wanted some more opinions before I do that.
I guess it is possible the wrong master cylinder was installed on the truck when I bought it, or multiple master cylinders will work on the truck. The other item of note is that it has disc in the front with two pistons.
The MC part listed on LMC has the brake lines on the left(different from my old MC) - picture attached. Part 45-4025.
Question, are the two parts I sourced wrong and I need to find an MC with the ports on the right side(like the old MC), or do I use one of these new ones and move the brake lines?
You could rebuild the old one. You might have to hone the bore or have someone else hone it for you depending on what the bore looks like. Usually a kit will get you going for a good while.
Looking at parts catalogs,it depends on what calipers you have. Single piston- ports are on the right. Dual piston-ports are on the left. That 45-4025 would fit trucks with dual pistons.Yours must have been replaced with the wrong part. IMO ,install the correct part and move the lines.
I don't have a F-250, I have a F-150 with single piston calipers, it had an 11" single diaphragm booster, and the lines went to the right side of the master cylinder. I chose to upgrade brakes.
I made changes years ago, mounted a F-350 9" dual diaphragm booster with F-350 master cylinder, the lines then were moved to come into the master cylinder on the left. I also put larger pistoned T-bird calipers in place.
Thank you, all. I will go with the MC with the ports on the left side as I think that is the correct part. I will then have to move the brake lines to the other side. Thank you for your help!
Sorry I've been away for a bit. My 1976 F250 SC trailer special has the original master. The lines on mine are on the left side. It has a bore of 1.25 inches. After ordering three different masters all different I did a rebuild on it. First one had the lines on the right, the second one had a 1 inch bore and the third gave me a push rod adjustment issue. Brakes are working like they did in 1976...
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