Repeated Clutch Master Cylinder Failure

[BftSupra]

I have the RPS 3200# Pressure plate with a sprung six puck disk on my car and it seams to be too much for the stock clutch master cylinders. I have gone through 1 used one from a parts car, 1 I rebuilt with toyota parts, and three discount auto replacements 1 cheap and 1 high end. I replaced the high end one under warranty a couple of months ago, but it is starting to fail again.

The first sign of failure is when the pedal coupling starts to wallow out and get loose. It is apparently a rubber link with the cylinder actuating rod and after a few months it gets loose and fails to apply all the pedal effort to the cylinder actuating rod. You can feel it getting loose in the pedal action along with an occaisional groaning when depressing the pedal. The next symptom is a steady decrease in the height of the point of engagement from the floor.

The clutch engagement has been about half way up from the floor since I first put the clutch in. The pedal adjustment is about as far out as I dare go with it. This coupled with the fidanza flywheel and very grabby clutch makes it kinda hard to enjoy driving in stop and start traffic. I like it fine when it has a brand new master cylinder, although a more normal point of engagement would be nice.

Is there some kind of upgrade to this whole pedal/cyl system which will dispense with this aggravation? Any one else have/solve this problem?

 

[bigaaron]

The 3200lb pressure plate might be too much for the master, but more importantly it is very hard on the thrust washer in the engine. I don't know why people keep buying those. If you really need that much clamping force, look into a multi-plate clutch.

 

[Silvermk2]

Yep, join the club. I'm about 4 master cylinders in now at about 800 miles. I just had the snap ring pull off the clutch hub as well. Unfortunately nobody makes a readily available multi-plate for the M-series/R154 combo.

 

[starscream5000]

If you really need that much clamping force, look into a multi-plate clutch.

I thought about saying something to this effect when I first read the post, but I didn't want to come across as arrogant or anything, but you were very professional in your approach to it . Too bad a good multiplate clutch system costs so damn much compared to what else is out there...

 

[BftSupra]

I don't "keep buying them", but I have driven this one with over 400 ft/lbs to the wheels for over 3 years and 30k miles, and it has held up well. At the time I bought this one, it was about the only one that claimed to hold 500+ lb/ft of torque, and I had read lots of stories about the failure of other clutches. The only multidisk I saw at the time was about $2k and had to be ordered from japan. I have only driven 1 multidisk(os-giken triple on an STI) and the engagement was even more harsh than this one. It chirped or stalled on every launch which has to be tough on the entire drivetrain.
These clutches are still available because they work and are reasonably priced. As a vendor, perhaps you should offer something with comparable capability and solve this problem for us all. I would gladly buy a product to make me happy driving this car again, but like most mk3 owners don't have a lot of cash to splash experimenting with new products.00000

I had a fresh engine when I installed this badboy and it seems to have held up so far, but the last master(aisin) is going out after only about a month this round. I don't have a big problem with replacing it, just can't stand notion of throw away parts, and frequent replacement maintenance on my car. I have only had to replace 1 slave, so the master is apears to be the weaker link.

I am hoping for a solution here, and a $2k clutch is not in the budget at this time. This must happen to other vehicles, too. I am still hoping for a solution in the form of a different setup or a mod to this setup.
I think the quicker engagement of the six puck could live with less travel from the slave, so perhaps a larger master from some other application would work. I would also try a different pedal setup to provide more leverage and less legwork, should there be one available.
Anyone with a solution or some viable options?

 

[IJ.]

An "alternative" would be to use a small remote booster like a VH44.

This will greatly reduce the pedal effort required.

Another risk you're all running is stress fractures of the firewall/bulkhead where the Master bolts on, haven't seen it in a Supra but have in a few other cars in the past.

 

[bigaaron]

I hear you guys on all those points, and I didn't want to come off as unsympathetic. I guess when you get into the big horsepower you gotta pay to play though. If you can't spend the money on the clutch, one possible option is to not make so much horsepower that a upgraded single plate clutch would slip. :dunno: Seriously though.... Like a piece of chain, the car is only as strong as it's weakest link. Leave the boost down a little while you save up for the right parts to handle your eventual horsepower goal. "Only" 500whp is nothing to be ashamed of, it's probably a lot of fun. (I'm not even there yet myself, but hopefully soon! LOL)

That's just my .02.

 

[Grimsta]

Pomona, right on BigAaron, i'm gonna be down there at Extreme Auto Fest in a few weeks, but yeah, multidisc is what i'm goin with. An ORC is what i'm going with, i'm not diggin the price but if 600hp is the goal, it must be done. I'll just work on a sponsorship, lol

 

[BftSupra]

The VH44 sounds good, but I only see pics of them as whole brake booster units. I don't see enough room on the firewall for that. If there is a remote booster, that would be cool, but I need more info about what it is and where to get one.

I think most people drive MK3s because they are sporty, readily available and pretty inexpensive to get into. If you have lots of funds an M3, Z06 or a Viper would have all these issues sorted out and really be fun to drive as well. The rest of us just have to keep sorting it out one piece at a time.
If I had thought I would spend over 10k on my Supra, I probably wouldn't have bothered, but here I am.

When I bought my car, it had a cartech cast manifold, cartech intercooler, t04b super-H turbo and haltech f3. It also had rod knock. Once I got the engine straightened out, the newish stock clutch slipped under boost with 390 rwhp. I looked into what everyone was using on 7mpower, and voila the rps max 3200 was the weapon of choice. Seemed like the right thing to do, and as I said, the only multiplate I saw was in Japan. I really don't want to wait 3 months for service if there is a problem like a missing or broken part. If you have not driven a multiplate clutch, you may be in for a big disapointment when it comes to street engagement, most of the ones I have heard about are pretty much on/off type engagement.

As to fun driving, you have no idea. It is a beast and nothing can touch you on the streets. It scares the crap out of anyone riding with you and probably riding near your car when you hit it hard. You don't just spool up for fun much, because the roar of the open w/g is pretty obnoxious. Leaving all the intersections at 2k rpms occaisionally gets some funny responses from slower sports enthusiasts like mustang gts and 350Zs. They occaisonally hit it hard when they think you are racing them. I do like to drive this car.

As to the turn the boost down till you get ready, well ,,, I bought a 240sx with an sr20det for about the cost of one of these new wonder clutches installed. I am planning to make about 350 rwhp in a 2600# car. Any part you can imagine is available on ebay for a fraction of the cost of an equivalent mk3 supra part. The lighter weight scales everything down in terms of cost vs. performance. Its a lot more like a kart than a caddie.

It would be nice to keep the supra and drive it when i feel like cruising, but this clutch system needs to be a little more reliable. I hate driving this car without a clutch, but have to get home when it fails. So far it has given it up slowly and I have not been stranded, but who know what the next time will bring.

 

[starscream5000]

the only multiplate I saw was in Japan. I really don't want to wait 3 months for service if there is a problem like a missing or broken part. If you have not driven a multiplate clutch, you may be in for a big disapointment when it comes to street engagement, most of the ones I have heard about are pretty much on/off type engagement.

I've heard nothing but good things about multiplate clutches on the MKIII's from those rare few that have them. Soft clutch pedal feel, and really easy to slip. Are you sure that you are talking about a multiplate from an actual MKIII supra, or have you been hearing these things from other people in different cars? :dunno:

 

[IJ.]

VH44 IS a remote booster you just plumb it in the line between the Master and Slave and a line to vaccum and you're good to go.

The 44 from memory is the smaller capacity and the 40 the larger.

 

[BftSupra]

Honestly, they were on rb25/26 nissans, mkiv supras or sube sti. All were pretty much the same story regarding 600+ ft/lbs capable clutches. I have seen no info at all about mk3 products with this capability. Which products are you talking about and what are the details as to availability and cost?

 

[Jason T]

I don't have a big problem with replacing it, just can't stand notion of throw away parts, and frequent replacement maintenance on my car. I have only had to replace 1 slave, so the master is apears to be the weaker link.

I am hoping for a solution here, and a $2k clutch is not in the budget at this time. This must happen to other vehicles, too. I am still hoping for a solution in the form of a different setup or a mod to this setup.

Try this http://www.speed-source.net/products/pushrod.htm

 

[BftSupra]

Thx Jason T, thats pretty much what I was thinking should be out there somewhere. I think I will give that a try. Not exactly the problem I have( the six puck disk fully disengages immediately), but it may move the pedal effort higher and change the stress on the master cylinder to a diferent spot.

IJ. I've got to wonder how the vacuum line will affect this as they seem to be brake boosters(off throttle when braking = lots of vacuum). Shifting at high boost will go from high pressure to lots of vacuum in a flash but where will you be in the clutch pedal stroke as this occurs. I almost never shift WOT, so maybe it will always be vacuum, but sometimes when I get in a hurry..... Or is it a reservoir type that saves up the vaccum till needed?
I will look into this more, though most of the references to this product are over on your side of the planet, meaning acquisition may be a challenge.

 

[IJ.]

Bft: This is the only pic I can find right now and yes it's a reservoir system just like the Brake booster just remote mounted/actuated as I said simple to plumb unlike the genuine Toyota Clutch booster that's inline the same as the stock brake booster..

 

[gilberjj]

im starting the install of my 2800lb action clutch from bigaaron today. ill post how it works on my build thread. im also replaceing my master cylinder with an asain (sp). i have all the parts, and it will be interesting to see how this 2800 relates to your 3200! im looking to put down 525 rwhp on race gas, and 425 on pump

 

[stephen7m]

hey guys, i've been reading this thread with some interest, im in the last stages of my rebuild/manual swap on my '89 7mgte. i chose the spec stage3+ clutch as im planning on a power hike in the future, and spec say this clutch is rated to 620lbs/ft although i dont know what the actual clamping force is.
just wondering if there has been any reports of it eating masters in the same way as the rps 3200 as mentioned at the start of the thread, be nice to know if i gotta start getting supplies of master cylinders in just now :biglaugh:

 

[starscream5000]

Honestly, they were on rb25/26 nissans, mkiv supras or sube sti. All were pretty much the same story regarding 600+ ft/lbs capable clutches. I have seen no info at all about mk3 products with this capability. Which products are you talking about and what are the details as to availability and cost?

Tilton. Cost. Expensive. Fitment. IIRC it is a pull type clutch, the opposite of the what the stock clutch and the upgrades are, so modifications are required.

OSGeiken (sp?). Pretty much the same here.

Search some of our vendors on here, I'm wanting to think that 935Motorsports may sell one. Also, IIRC horsepowerfreaks sells a multiplate.

You're looking at a $3000.00 clutch here easily....