Booster/MC Upgrade Question

protonvx

NAXJA Member
NAXJA Member
Planning on using a booster from a 95/96 on my 92. Do I need to use the master cylinder from the same year as the booster or can I use the master cylinder that is in there now?
 

markw

web wheeler
NAXJA Member
They're all 1" master cylinders. It's easier to do the whole unit with master cylinder/proportioning valve though.
 

Jim Malcolm

New member
You'll need master cylinder as well, regardless of what dual diaphragm brake booster you use. The 95-01 XJ master cylinder is much different than the 90-94. Ports are metric bubble, so you'll need new lines. I got premade ones with the metric bubble fittings and flared them for the standard fittings. Worth every bit of hassle.
 

paulhead

I overtighten $#!t
NAXJA Member
Planning on using a booster from a 95/96 on my 92. Do I need to use the master cylinder from the same year as the booster or can I use the master cylinder that is in there now?
Do a write up :D I'm doing this soon
 

protonvx

NAXJA Member
NAXJA Member
You'll need master cylinder as well, regardless of what dual diaphragm brake booster you use. The 95-01 XJ master cylinder is much different than the 90-94. Ports are metric bubble, so you'll need new lines. I got premade ones with the metric bubble fittings and flared them for the standard fittings. Worth every bit of hassle.
I know the two are different which is why I would prefer to keep the one that is in perfect working condition on there. I just want the benefits of the dual diaphragm booster. Everything I have read states that the booster is the upgrade not really the master cylinder although I might have missed something. If I have missed something feel free to let me know.
 

protonvx

NAXJA Member
NAXJA Member
Do a write up :D I'm doing this soon
Plenty of write ups already out there. But everyone I have come across involves changing the master cylinder along with the booster. I am just being lazy and cheap and don’t want to replace the master cylinder I have now unless I have to.
 

Dragonlich1961

New member
i would recomend going to a junkyard and pulling the lines and prop valve off of the required donor vechile, as well as the spacer plate under the booster. simplfies the whole install greatly. just be cafe, on the rear port of the propvalve there is a dummy cap used on abs models, this cap needs to be removed and replaced with a non abs model one to allow for the second front line to connect to the valve.
I swapped my 94 abs to 96 non-abs, but the doner was abs. not relizing the valve i had to return to said jy and fetch the missing cap.
simplied teh install greatly, since the lines out off the valve are sae not metric
 

protonvx

NAXJA Member
NAXJA Member
i would recomend going to a junkyard and pulling the lines and prop valve off of the required donor vechile, as well as the spacer plate under the booster. simplfies the whole install greatly. just be cafe, on the rear port of the propvalve there is a dummy cap used on abs models, this cap needs to be removed and replaced with a non abs model one to allow for the second front line to connect to the valve.
I swapped my 94 abs to 96 non-abs, but the doner was abs. not relizing the valve i had to return to said jy and fetch the missing cap.
simplied teh install greatly, since the lines out off the valve are sae not metric
Thanks for the advice, but I am buying new. Got burnt on the first used setup I bought when I discovered the the booster was full of fluid after I already had it at home. Secondly the junk yards in my area want a small fortune for parts. So if I need to replace lines and fittings, I will be making my own.
 

Dragonlich1961

New member
not booster or master, i wouldn't trust a jy unit. just simply the lines and valve and bracekt. nothing can go wrong with those parts. saved me a huge head ache making by not having to make the metric lines, for which i don't have the tool to do so. i have sae.
 

protonvx

NAXJA Member
NAXJA Member
not booster or master, i wouldn't trust a jy unit. just simply the lines and valve and bracekt. nothing can go wrong with those parts. saved me a huge head ache making by not having to make the metric lines, for which i don't have the tool to do so. i have sae.
Gotcha. I will have to call and see if they will sell them separately.
 

protonvx

NAXJA Member
NAXJA Member
Would still like to know if anyone knows if I can use my current master cylinder with the newer booster. It has been pointed out that the master cylinders are the same bore. But don’t know if they will mate together correctly...
 

Jim Malcolm

New member
As I said above, you have no choice but to change the master cylinder. I have personally done this swap and am 100% certain of it. Use rockauto.com to pull up pictures of the master cylinder and power brake booster from both years and it will be obvious that the are not the same.
 

protonvx

NAXJA Member
NAXJA Member
As I said above, you have no choice but to change the master cylinder. I have personally done this swap and am 100% certain of it. Use rockauto.com to pull up pictures of the master cylinder and power brake booster from both years and it will be obvious that the are not the same.
I know they look different and I know they have different size fittings. I also know the bore is the same as posted earlier in this thread and I have also verified from a couple other people. I just don’t know why the 92 mc won’t work on the 95 booster. Jim, why won’t they work together? I am not doubting you, just asking a question. Thanks in advance.
 

Jim Malcolm

New member
It's the interface between the two. On the early ones, the rod in the power booster sticks out beyond the face of the booster. The master cylinder has a large diameter, short length protrusion to locate and seal itself on the booster. On the 95-96, the rod in the booster does not extend out of the housing and the MC has a long narrow protrusion. You won't physically be able to slip the earlier MC into the 95-96 booster because the hole in the booster is too small and the 95-96 MC wouldn't seal against the earlier booster because the hole will be too big. If you really wanted to get creative, you could open up the hole in the 95-96 booster and make an extension for the rod but I assumed that was beyond the scope of your question.
 
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