Spokerider
01-19-2016, 11:00 AM
I have just rebuilt some rear 1992 240sx calipers to be used on my Suzuki Samurai rear disc brake conversion.
They sure aren't a straight forward rebuild like "regular" front calipers, as the parking brake mechanism parts complicates the rebuild. I never did take them "totally" apart, ie; the parking brake push rod parts, as I need some long thin snap ring pliers to get to a snap ring, deep in the bottom of the piston bore. Anyway, on to my question.........
Both calipers seem to work [ properly ] on the same principle.....to move the piston out in it's bore, you activate the parking brake arm on the caliper, and it pushes the piston out a tiny bit with each stroke. This is how slack adjustment is made on them. I'm sure you know this. However, on my calipers, each caliper moves the piston out at a different rate per number of strokes. On one side, 7 lever strokes moves the piston out about 3/4" on one side, the other caliper requires about 30-40 strokes to get the same amount of piston travel. This is pre and post rebuild, and as mentioned, I did not get into the parking mechanism parts on these calipers yet.
At first, I thot that the caliper wasn't functioning correctly, but when I screwed the pistons back into the respective bores, I noted that one side [ the 30-40 stroke side ] needed 5 times as many rotations of the piston to seat it fully back into it's bore. Also, I noted that both caliper pistons moved out the same amount with a full stroke of the parking brake lever, just that the one caliper piston retracted more back into it's bore upon releasing the parking brake lever. Based on this observation, am I safe to assume that the "gripping force" on the rotor will be the same on these calipers when the parking brake is pulled?
So, they both seem to work well?, both are for a 240sx, but just need different numbers of strokes for adjusting them. Both calipers look the same, but have different numbers / letters stamped on them. They were both off the same donor car. Is this normal to find this difference among rear calipers? Or could the one requiring many strokes be buggered? I know there are a few different manufacturers for these....Centric, Raybestos, Wagner, Dorman, etc.
Anyone else come across this?
Is one of them buggered?
First time rebuilding rear calipers like this, thus my questions, and no one on the Samurai forums that I regularly visit seem to know.
I just bought some long nosed snap ring pliers, so I may have a second crack at getting that deep piston bore snap ring out. and replacing that last small O ring on the push rod.
Thanks for your thoughts!
They sure aren't a straight forward rebuild like "regular" front calipers, as the parking brake mechanism parts complicates the rebuild. I never did take them "totally" apart, ie; the parking brake push rod parts, as I need some long thin snap ring pliers to get to a snap ring, deep in the bottom of the piston bore. Anyway, on to my question.........
Both calipers seem to work [ properly ] on the same principle.....to move the piston out in it's bore, you activate the parking brake arm on the caliper, and it pushes the piston out a tiny bit with each stroke. This is how slack adjustment is made on them. I'm sure you know this. However, on my calipers, each caliper moves the piston out at a different rate per number of strokes. On one side, 7 lever strokes moves the piston out about 3/4" on one side, the other caliper requires about 30-40 strokes to get the same amount of piston travel. This is pre and post rebuild, and as mentioned, I did not get into the parking mechanism parts on these calipers yet.
At first, I thot that the caliper wasn't functioning correctly, but when I screwed the pistons back into the respective bores, I noted that one side [ the 30-40 stroke side ] needed 5 times as many rotations of the piston to seat it fully back into it's bore. Also, I noted that both caliper pistons moved out the same amount with a full stroke of the parking brake lever, just that the one caliper piston retracted more back into it's bore upon releasing the parking brake lever. Based on this observation, am I safe to assume that the "gripping force" on the rotor will be the same on these calipers when the parking brake is pulled?
So, they both seem to work well?, both are for a 240sx, but just need different numbers of strokes for adjusting them. Both calipers look the same, but have different numbers / letters stamped on them. They were both off the same donor car. Is this normal to find this difference among rear calipers? Or could the one requiring many strokes be buggered? I know there are a few different manufacturers for these....Centric, Raybestos, Wagner, Dorman, etc.
Anyone else come across this?
Is one of them buggered?
First time rebuilding rear calipers like this, thus my questions, and no one on the Samurai forums that I regularly visit seem to know.
I just bought some long nosed snap ring pliers, so I may have a second crack at getting that deep piston bore snap ring out. and replacing that last small O ring on the push rod.
Thanks for your thoughts!