JMC Hydraulic Clutch and Power Brakes

jcode68 · Sep 27, 2005

I'm moving forward with my driveline upgrade and getting ready to finalize my transmission parts order. I am installing a T-5z trans and late model bellhousing, 10.5 clutch etc. I have read many threads on this forum about the pros and cons of cable versus hydraulic clutch and have decided to go with the JMC hydraulic unit mainly for header clearance and asthetic reasons. I will be running Hooker Comp headers, not shorties, so I don't want/need the problems with the cable. I am also looking to upgrade my front brakes in the near future from the current manual drums all around to front disc and understand the JMC unit has compatibility issues with some power brake systems. My questions are:

1)which systems are compatible with the JMC system?
2)Is anyone running non-power disc brake setup and how responsive/happy are you with this choice? Any plans to upgrade to power?

I haven't chosen a brake system yet, but was leaning in the direction of something like an SSBC Force 10 setup compatible with the 15 inch Tourque Thrusts I am already running. Thanks in advance for all your opinions.

5.0ina66 · Sep 27, 2005

A 90 mustang GT booster is proven to fit in a 67-68 with the JMC setup. This is what ultrastang has in his 67.
HTH
--Kyle

red65 · Sep 27, 2005

I have the JMC hydraulic clutch and four-wheel non-power discs. The brakes are no problem at all for me - they require some force, particularly in hard stops, but it's pretty manageable. I actually like the 'in-touch-with-the-car' feeling that non-power brakes give you. However, the pedal effort required for a hard stop by someone of smaller stature could be a problem. My wife tells me she's not sure she could stop super-fast in the car, because of the pedal effort (that's kinda good - keeps her tame while driving it!) FYI - I'm 6' 190lb, she's 5'2" 110lb...

No problems, btw, with the JMC clutch kit - pretty happy with it. JMC was responsive when I called with a problem, and I really haven't messed with it since putting it in. Some people on this board have had problems bleeding the system, but I had no problems at all - just followed the directions that came with the kit.

Hope that helps

jcode68 · Sep 27, 2005

5.0ina66 said:
A 90 mustang GT booster is proven to fit in a 67-68 with the JMC setup. This is what ultrastang has in his 67.
HTH
--Kyle

Thanks for the info, this is helpful. Would love to see some pictures of ultrastang's setup. Any links? What caliper kits would the 90 booster be compatible with? Compatible with front disc, rear drum? Thanks.

jcode68 · Sep 27, 2005

red65 said:
I have the JMC hydraulic clutch and four-wheel non-power discs. The brakes are no problem at all for me - they require some force, particularly in hard stops, but it's pretty manageable. I actually like the 'in-touch-with-the-car' feeling that non-power brakes give you. However, the pedal effort required for a hard stop by someone of smaller stature could be a problem. My wife tells me she's not sure she could stop super-fast in the car, because of the pedal effort (that's kinda good - keeps her tame while driving it!) FYI - I'm 6' 190lb, she's 5'2" 110lb...

No problems, btw, with the JMC clutch kit - pretty happy with it. JMC was responsive when I called with a problem, and I really haven't messed with it since putting it in. Some people on this board have had problems bleeding the system, but I had no problems at all - just followed the directions that came with the kit.

Hope that helps

I read the threads where people had issues bleeding the system. Seemed like patience was all that was really required in the end. Right now with 4 wheel manual drum brakes, it takes a lot of force to stop the car. It flat out sucks and it's hard to believe people used to drive daily with these setups. I'm sure manual disc would be a dramatic improvement, but I'm probably going to want power brakes if I can get it all to work together. Would love to here from or see some pictures of Stangs who have figured out the best setup for this.

1Bad67 · Sep 27, 2005

I'm running the JMC system with the factory '67 booster. It fit with no problem.

gsxrken · Sep 27, 2005

My JMC kit tucked in below and to the drivers side of the stock power disc booster. If there is any fitment issues that you heard of, they are not with the 69's.

5.0ina66 · Sep 27, 2005

jcode68 said:
Thanks for the info, this is helpful. Would love to see some pictures of ultrastang's setup. Any links? What caliper kits would the 90 booster be compatible with? Compatible with front disc, rear drum? Thanks.

It's compatible with all brake setups (disk/disk, disc/drum, ect), as its just a booster.
http://www.ultrastang.com/Ultrainfo.asp?Page_ID=16 is the site.
HTH
--Kyle
PS: If it fits with the stock booster...

mdjay · Sep 27, 2005

The JMC Hyd Clutch Kit is not compatible with the 7" booster they make for the 65-66 cars. There's not enough clearance for the Clutch Master where it comes through the firewall. It might work with a smaller booster but I have yet to see one successfully installed. I had to ditch my booster and master and went with the JMC bias bar set-up. It does stop pretty good when you put your foot through the floor, but I'm missing the booster. 1967-Up should not have any problems with the JMC kit.

jcode68 · Sep 28, 2005

mdjay said:
The JMC Hyd Clutch Kit is not compatible with the 7" booster they make for the 65-66 cars. There's not enough clearance for the Clutch Master where it comes through the firewall. It might work with a smaller booster but I have yet to see one successfully installed. I had to ditch my booster and master and went with the JMC bias bar set-up. It does stop pretty good when you put your foot through the floor, but I'm missing the booster. 1967-Up should not have any problems with the JMC kit.

Thanks mdjay. So if I got this right, my 68 should not have an interference problem with the JMC MC and either a stock or most aftermarket (such as SSBC or maybe Baer) power booster setups? Anyone out there with a similar setup in use? Can you post a pic?

STSFCTN67 · Sep 28, 2005

I have done the manual to power and have done the JMC swap as well. I went with the origianal OEM booster but I did have to change the brake pedal out. There are 2 types of brake boosters make sure you get the unit for power disc brakes and not power drums (clamp style). Make sure you include an adjustable proportioning valve when you intall the booster and you can use your existing proportioning block. (I learned this lesson the hard way on my first 67 back in '91 when I did the swap. I was cutoff and the driver in front of me slammed on his brakes and so did I. The rear brakes locked up doing 65mph and the car did a 360 on the highway - install the adjustable proportioning valve!)

With the JMC system, follow the directions to the tee and you will be fine. The mistake I made was I attached the pedal to the slave cylinder to soon and the system would not bleed. Just make sure there is no pressure on the slave cylinder and the system will bleed as you would expect.

I also did the T5z swap and I used the King Cobra clutch kit. See signature

jcode68 · Sep 28, 2005

STSFCTN67 said:
I have done the manual to power and have done the JMC swap as well. I went with the origianal OEM booster but I did have to change the brake pedal out. There are 2 types of brake boosters make sure you get the unit for power disc brakes and not power drums (clamp style). Make sure you include an adjustable proportioning valve when you intall the booster and you can use your existing proportioning block. (I learned this lesson the hard way on my first 67 back in '91 when I did the swap. I was cutoff and the driver in front of me slammed on his brakes and so did I. The rear brakes locked up doing 65mph and the car did a 360 on the highway - install the adjustable proportioning valve!)

With the JMC system, follow the directions to the tee and you will be fine. The mistake I made was I attached the pedal to the slave cylinder to soon and the system would not bleed. Just make sure there is no pressure on the slave cylinder and the system will bleed as you would expect.

I also did the T5z swap and I used the King Cobra clutch kit. See signature

Wow, doing a 360 at 65 mph on a highway is not my idea of a good time! I think most of the kits I have seen include the adjustable proportioning valve, I will make sure I get it. Sounds like everything will work fine with the future upgrades I have planned. Do you have any pics of your PB and JMC setup?

mdjay · Sep 28, 2005

STSFCTN67 said:
I have done the manual to power and have done the JMC swap as well. I went with the origianal OEM booster but I did have to change the brake pedal out. There are 2 types of brake boosters make sure you get the unit for power disc brakes and not power drums (clamp style). Make sure you include an adjustable proportioning valve when you intall the booster and you can use your existing proportioning block. (I learned this lesson the hard way on my first 67 back in '91 when I did the swap. I was cutoff and the driver in front of me slammed on his brakes and so did I. The rear brakes locked up doing 65mph and the car did a 360 on the highway - install the adjustable proportioning valve!)

With the JMC system, follow the directions to the tee and you will be fine. The mistake I made was I attached the pedal to the slave cylinder to soon and the system would not bleed. Just make sure there is no pressure on the slave cylinder and the system will bleed as you would expect.

I also did the T5z swap and I used the King Cobra clutch kit. See signature

This is a debate that is generally straight forward. It's always a good idea to be able to control the hydraulics on the rear separately from the front, no arguement. However, you can run it without if you adjust the rears out properly. It's a tedious process with a brake butterfly tool, but you can get them to work correctly.

JMC Hydraulic Clutch and Power Brakes

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