beatupjeep
02-21-2015, 05:36 PM
89 XJ Manual 4.0
On 3rd clutch master cylinder since I've owned it for 5 years, and now this one is bad too.
Took it apart to see whats going on.
No leaks in engine compartment.
Just leaking fluid above the clutch pedal. Can see the drip on the pushrod and dust cap.
Taking it apart I see what looks like corrosion under the dust cap.
Removing the plunger assembly I see and feel scratches in the bore.
I measured the electrical resistance of the bore at several spots, to the outside of the housing, and it was a short every time. This suggests that the bore is NOT anodized and is just soft aluminum. Im not sure what scratches it. There appears to be corrosion where the piston "sits", and also at both ends of the bore internally. Perhaps the steel/iron piston and the aluminum bore corrode when sitting from moisture in the air? Ive seen that happen inside cast iron blocks where aluminum pistons were allowed to sit.
This master cylinder was from autozone, probably part number 12960.
Autozone and oreilly seem to have only the aluminum ones.
Just looking at it, seems like rockauto may have cast iron ones.
I would take cast iron over un-anodized aluminum. Im not 100% sure whats going on here, but it seems like soft aluminum in a situation like this is asking for failure.
Looking at this, it makes me wonder if we could have the housings internally anodized, and then make sure to really clean the plunger assy before installing it, and these would work fine. Something is clearly scratching the bore.
Does anybody know how aftermarket master cylinders are designed?
I would really like to make one for our jeeps, but Id want to throw all the bells and whistles into it.
Does anyone know of a master cylinder design that is bulletproof that we could adapt to the jeep?
http://i242.photobucket.com/albums/ff197/acannell/20150221_152818_zpsjhdu6id7.jpg (http://s242.photobucket.com/user/acannell/media/20150221_152818_zpsjhdu6id7.jpg.html)
http://i242.photobucket.com/albums/ff197/acannell/20150221_152826_zpsrn2izm1e.jpg (http://s242.photobucket.com/user/acannell/media/20150221_152826_zpsrn2izm1e.jpg.html)
http://i242.photobucket.com/albums/ff197/acannell/20150221_152829_zpsamhzx6f6.jpg (http://s242.photobucket.com/user/acannell/media/20150221_152829_zpsamhzx6f6.jpg.html)
On 3rd clutch master cylinder since I've owned it for 5 years, and now this one is bad too.
Took it apart to see whats going on.
No leaks in engine compartment.
Just leaking fluid above the clutch pedal. Can see the drip on the pushrod and dust cap.
Taking it apart I see what looks like corrosion under the dust cap.
Removing the plunger assembly I see and feel scratches in the bore.
I measured the electrical resistance of the bore at several spots, to the outside of the housing, and it was a short every time. This suggests that the bore is NOT anodized and is just soft aluminum. Im not sure what scratches it. There appears to be corrosion where the piston "sits", and also at both ends of the bore internally. Perhaps the steel/iron piston and the aluminum bore corrode when sitting from moisture in the air? Ive seen that happen inside cast iron blocks where aluminum pistons were allowed to sit.
This master cylinder was from autozone, probably part number 12960.
Autozone and oreilly seem to have only the aluminum ones.
Just looking at it, seems like rockauto may have cast iron ones.
I would take cast iron over un-anodized aluminum. Im not 100% sure whats going on here, but it seems like soft aluminum in a situation like this is asking for failure.
Looking at this, it makes me wonder if we could have the housings internally anodized, and then make sure to really clean the plunger assy before installing it, and these would work fine. Something is clearly scratching the bore.
Does anybody know how aftermarket master cylinders are designed?
I would really like to make one for our jeeps, but Id want to throw all the bells and whistles into it.
Does anyone know of a master cylinder design that is bulletproof that we could adapt to the jeep?
http://i242.photobucket.com/albums/ff197/acannell/20150221_152818_zpsjhdu6id7.jpg (http://s242.photobucket.com/user/acannell/media/20150221_152818_zpsjhdu6id7.jpg.html)
http://i242.photobucket.com/albums/ff197/acannell/20150221_152826_zpsrn2izm1e.jpg (http://s242.photobucket.com/user/acannell/media/20150221_152826_zpsrn2izm1e.jpg.html)
http://i242.photobucket.com/albums/ff197/acannell/20150221_152829_zpsamhzx6f6.jpg (http://s242.photobucket.com/user/acannell/media/20150221_152829_zpsamhzx6f6.jpg.html)