Anyone use the RJM Performance clutch master cylinder?

[cavero]

Quick background -- back in February I upgraded to a 6 spd (T56 Magnum XL), and it's been awesome. But while I always had problems with 2nd gear fighting me from time to time (just figured that's how the transmission was), lately it's started grinding unless I'm driving like a granny (like shifting below 2000 RPM) or being ultra-precise with my shifts. Downshifting into 2nd is very touch and go so I don't even try.
I got in touch with Tremec and they said it's gotta be the clutch. The grinding would only happen if the synchros were toast or the input shaft was still being torqued. It's only got 1600 miles on it of around town driving with a few aggressive shifts, so leaning towards the clutch. It's a new McCleod Street Pro, with a new slave cylinder, but the master is original.
I mentioned the '13 GT500 master cylinder upgrade I've read about on this forum or another to my speed shop, asking if the extra throw would help make sure the clutch was fully disengaging. And they said check out this one instead:

RJM Performance Stage 2:
http://www.rjmperformance.com/05-14-mustang-gtgt500.html

It's the same idea behind putting the '13 GT500 in the GT, but this one's adjustable. The guy has a good thread over on SVTPerformance
https://www.svtperformance.com/forums/threads/project-large-bore-master-cylinder.1130794/


Anyone use it? or at least heard of it? It's a lot more expensive than the '13 MC, but still a lot cheaper than killing my synchros. And Tremec won't cover it under warranty if it's a clutch problem.


The shop is going to look over the car on Thursday, but starting to look at my options here.

 

[cavero]

Anyone even hear of them?

 

[cavero]

I contacted them through their website, here's what they have to say about it:

- No one's heard of it because it's only been available for the last couple weeks
- He said it it's any consolation, Fathouse Fabrication was using one of his first units on their Coyote that ran 8's! Pretty good bragging rights

- The Stage 2 is the same bore & stroke as the GT500 master cylinder, stage 3 is 15% larger.
- The difference between this one and the Shelby MC is mostly plastic and non-adjustable, whereas his are all metal, have Tilton internals, and the rod end is adjustable so you can tune it in to exactly where you want the pedal's engagement point to be.


Decisions.... I can spend $80 (Shelby) to see if the bigger master cylinder is going to fix my problem, even though it's not adjustable so it could really throw off my engagement point, and I could have it by next week...or I can spend over triple that amount for the MC from hell that I could dial in exactly the way I want it,I'd have to wait till the end of the month to get it though since he builds them all to order.

 

[EBABlacknChrome]

Sounds like a quality part and worth the wait IMO.

Sent from my SM-G930V using Tapatalk

 

[1950StangJump$]

I have my doubts that this is the problem with your second gear.

The Magnums are great, but not beyond reproach. Years ago, I had to have one replaced under warranty in an '11 Coyote because of some crazy noise. Seems to me that, if your clutch wasn't fully disengaging, you'd have grinding problems in more than 2nd gear. In particular, you'd notice much more effort required to get it into first from a stop. At the least, all the gears would have a grinding problem to some extent.

Given the $ you have invested so far, having the best master cylinder sounds like a relatively cheap, worthwhile investment. But, I'm betting some transmission warranty work is still in your future.

Did JPC do the install?

 

[cavero]

Yeah that's what I would've thought too, but I had a similar issue in my original 3650 where it'd lock out or grind 3rd gear. Turned out that the pressure plate bolts had backed out enough that the fingers weren't centered anymore and I wasn't getting full disengagement. By that point I'd already had my brain set on the Magnum so used that as my excuse to upgrade. I got in touch with Tremec tech support and started a warranty claim a few weeks ago and with all the symptoms I'm having they insist it's gotta be there's still torque on the input shaft. I asked why is every other gear fine (and BTW 2nd gear is the only carbon synchro, the rest are brass), and he said they're fine for now but if it isn't corrected they could all start doing it.

I'm hoping this fixes it -- but it does make me wonder if what I should be hoping for is that the clutch isn't the problem, and I can get it replaced under warranty. For now, I'll probably get the beefy master cylinder.

No JPC, I had American High Performance do it, they're a great shop local to me that's been in business for decades that does top notch work. They've done 6 of these Magnums before mine, so it's not like its their first one iether. The transmission itself and the installation kit I bought from D&D Performance.

 

[1950StangJump$]

American High Performance put the clutch in mine also back in October (Spec Stage 2 in a TR3650). Seemed descent enough, though I think they are a notch below the caliber of JPC. But, you pay for that quality with JPC.

 

[cavero]

AHP's always done right by me. How do you judge the caliber? Just wondering. What sort of work did you have JPC do?

Its funny, I googled JPC to see where they were (didn't realize they were right over in MD) and I saw that same black convertible GT500E that shows up in their google results over at AHP the other week.

 

[cgornowich]

My T56 Magnum XL seemed to have a problem with a grinding noise in 3rd and 4th gear, below 2,000 rpm. I contacted Tremec, removed the trans, boxed it up and paid to send it to them. 10 days later it was returned with a letter stating it was fine, the issue was the clutch. It was obvious that the trans had been disassembled and there were grease marked numbers in different colors in a few locations. Not only did they waive the inspection fee and return shipping fee, but they were right about the problem. It was the clutch...

Tremec did right by me.

 

[cavero]

Yeah I'm going to go the clutch route before I box up the transmission (luckily i kept the box though). Ordered the RJM master, should be here next week

 

[cavero]

Well, took a month (the guy was on vacation for 2 weeks), but I finally got it. Beefy.






Those cracking problems the stock eyelet has? Yeah not gonna happen

 

[cavero]

As far as the install went, it was pretty smooth once I got the pedal assembly out of the car. That part sucked bad, but it was a lot easier than it would've been trying to swap the MC with the pedals still in the car. The only part that was different from a typical clutch master replacement was adjusting the rod on the new MC, which was pretty dead simple. You basically just loosen the jamb nut and turn the rod until the piston hits full stroke at the same time the pedal hits the bump stop. Too short and you won't get a full stroke with the full pedal travel, too long and you can damage the MC over time.

Driving impressions? A hell of a lot more positive feeling than the stock one -- it feels SOLID, but a lot heavier too. They say about 15% heavier than stock but to me it feels like 50% over what it was before. Then again the clutch was surprisingly light after I got the new transmission. Makes me wonder if it was bypassing internally. All that said, my transmission still grinds going down into 2nd over 10 mph, so I'm wondering if the damage is done and my synchro might be toast.

 

[1950StangJump$]

Sorry it didn't fix your problem. At least you have a quality part for when you get the tranny fixed (under warranty, hopefully).