vetteboy
NAXJA Forum User
- Location
- morganville, nj
They're the same, M12 and M10.
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E350 Master Cylinder Questions
- Thread starter jdbwrx
- Start date
vetteboy
NAXJA Forum User
- Location
- morganville, nj
The '99 is definitely the one to go with. Here are some comparison pics...
(L to R): Stock ZJ, '99 Dodge 2500, '94 Dodge 2500
The ZJ and the '99 are directly interchangeable for mounting. The seal and bolt pattern are the same. Both use M12-1.0 and M10-1.0 double-flare outlets. From what I measured, the pushrod needs to be extended 5/8", or a spacer put in the bore of the MC itself.
The '94 on the other hand, has a slightly wider bolt spacing, a different seal, 1/2" and 9/16" single-flare outlets, and a reservoir that doesn't clear the hood. I'm not sure where I got the reference for this one originally, but it's not the right one to use.
Keep in mind that this is NOT a good solution for anyone running stock axles. You will not get better braking performance out of a 3/4- or 1-ton MC unless you've got 3/4- or 1-ton brakes. I'm running the large single-piston D60 calipers in the front of mine.
The smaller bore of the ZJ MC meant that I had plenty of braking power available, but at the expense of a soft pedal feel and excessive pedal travel. It always worked and would lock all 4 tires up, but if I really stood on it the pedal would go nearly to the floor even when fully bled. The small bore just doesn't push enough fluid to fill the large calipers with the normal pedal stroke.
By going to the 2500 MC, it'll require a little more braking effort on my part, but the pedal travel will be normal and it'll feel like a "stock" system again.
(L to R): Stock ZJ, '99 Dodge 2500, '94 Dodge 2500
The ZJ and the '99 are directly interchangeable for mounting. The seal and bolt pattern are the same. Both use M12-1.0 and M10-1.0 double-flare outlets. From what I measured, the pushrod needs to be extended 5/8", or a spacer put in the bore of the MC itself.
The '94 on the other hand, has a slightly wider bolt spacing, a different seal, 1/2" and 9/16" single-flare outlets, and a reservoir that doesn't clear the hood. I'm not sure where I got the reference for this one originally, but it's not the right one to use.
Keep in mind that this is NOT a good solution for anyone running stock axles. You will not get better braking performance out of a 3/4- or 1-ton MC unless you've got 3/4- or 1-ton brakes. I'm running the large single-piston D60 calipers in the front of mine.
The smaller bore of the ZJ MC meant that I had plenty of braking power available, but at the expense of a soft pedal feel and excessive pedal travel. It always worked and would lock all 4 tires up, but if I really stood on it the pedal would go nearly to the floor even when fully bled. The small bore just doesn't push enough fluid to fill the large calipers with the normal pedal stroke.
By going to the 2500 MC, it'll require a little more braking effort on my part, but the pedal travel will be normal and it'll feel like a "stock" system again.
Andy in Pa.
NAXJA Member #180
- Location
- Downingtown, Pa.
Hey Vetteboy, did you ever do this swap? How did it turn out? I have to do something soon with my 96 XJ... HPD44 front, Ford outers/XJ D44 rear w/ZJ disk brakes. It has been getting progressively worse trying to stop 5.13 gears w/4:1.
I lost all brakes at NAC-Fest, but they came back after pumping the pedal a bit. Found the seal inside the cap of the MC expanded to the point where I couldn't get it back in without using my pen-knife to squeeze it in while putting the cap back on.
Its time for an upgrade...
Andy
I lost all brakes at NAC-Fest, but they came back after pumping the pedal a bit. Found the seal inside the cap of the MC expanded to the point where I couldn't get it back in without using my pen-knife to squeeze it in while putting the cap back on.
Its time for an upgrade...
Andy
vetteboy
NAXJA Forum User
- Location
- morganville, nj
Yep, sure did. Bolted right up and all the lines connected easily.
I took a 10mm shoulder bolt and cut a little 5/8" chunk out of it to make a pushrod spacer, which I dropped down the bore of the MC before I installed it. It's close but not quite...needs to be just a tiny bit longer. I can feel in the pedal that it uses the first 20% of travel before the pushrod makes contact with the piston.
But, even so, it's noticeably better. Even with the excessive free play the pedal goes just about as far as it did with the ZJ MC in 100% 'calibrated' shape. If I ever get around to messing with the spacer again it'll get even better, but once the lines are hooked up it's kind of annoying to keep taking it off and testing. Spend the time at the start to get it right and you'll be much happier.
This is how it looks installed:
You shouldn't have to modify the hood at all - but definitely check before you slam it shut.
I took a 10mm shoulder bolt and cut a little 5/8" chunk out of it to make a pushrod spacer, which I dropped down the bore of the MC before I installed it. It's close but not quite...needs to be just a tiny bit longer. I can feel in the pedal that it uses the first 20% of travel before the pushrod makes contact with the piston.
But, even so, it's noticeably better. Even with the excessive free play the pedal goes just about as far as it did with the ZJ MC in 100% 'calibrated' shape. If I ever get around to messing with the spacer again it'll get even better, but once the lines are hooked up it's kind of annoying to keep taking it off and testing. Spend the time at the start to get it right and you'll be much happier.
This is how it looks installed:
You shouldn't have to modify the hood at all - but definitely check before you slam it shut.
Andy in Pa.
NAXJA Member #180
- Location
- Downingtown, Pa.
vetteboy said:Yep, sure did. Bolted right up and all the lines connected easily.
I took a 10mm shoulder bolt and cut a little 5/8" chunk out of it to make a pushrod spacer, which I dropped down the bore of the MC before I installed it. It's close but not quite...needs to be just a tiny bit longer. I can feel in the pedal that it uses the first 20% of travel before the pushrod makes contact with the piston.
But, even so, it's noticeably better. Even with the excessive free play the pedal goes just about as far as it did with the ZJ MC in 100% 'calibrated' shape. If I ever get around to messing with the spacer again it'll get even better, but once the lines are hooked up it's kind of annoying to keep taking it off and testing. Spend the time at the start to get it right and you'll be much happier.
This is how it looks installed:
You shouldn't have to modify the hood at all - but definitely check before you slam it shut.
Good stuff, thanks Chris. A friend is giving me a new E350 MC to try, it seems there is mixed reviews with one of these, so maybe I'll just do the 2500 MC instead. This, plus a new "stock" booster (dual diaphragm) is my plans right now. I do not run a factory-style proportion valve, took it out and ran the lines direct to the front wheels, and ran through an adjustable prop valve (mounted in-cab)to the rear ZJ disks. It seemed like a good idea at the time to take out the factory prop valve, since it mostly controls the rear braking anyway.
A.
vetteboy
NAXJA Forum User
- Location
- morganville, nj
I've never tried an E350 master. I bought one and realized it was TOTALLY wrong for my booster and promptly returned it. That, or the Corvette one, is the one to use with the older single-diaphragm booster. The Corvette booster is preferred for rear disc setups; the E350 for drum.
They changed the seal and some other stuff on the dual-diaphragm one, which is why you gotta use the newer Dodge MC with it.
edit: I'm running the ZJ proportioning valve from one that had rear discs. Seems to work OK, the front wheels lock first, and I've never really had a reason to mess with it.
They changed the seal and some other stuff on the dual-diaphragm one, which is why you gotta use the newer Dodge MC with it.
edit: I'm running the ZJ proportioning valve from one that had rear discs. Seems to work OK, the front wheels lock first, and I've never really had a reason to mess with it.
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Andy in Pa.
NAXJA Member #180
- Location
- Downingtown, Pa.
vetteboy said:
Ah, OK, so your running the dual diaphragm booster too then?? I am assuming that is the booster I have, since I have a 96 and the stock MC with the plastic reservoir. Is that right?
A.
vetteboy
NAXJA Forum User
- Location
- morganville, nj
Yep...mine was one of the last '94s made, which had switched over to a lot of '95 parts at that point, one of which being the newer booster. If you've got the plastic reservoir instead of the one with the metal cap and spring clip, you're probably looking at the same one I am.
