[shorttrack]

I'm in the process of adapting a different clutch cylinder (metal) in place of the junk plastic unit in our cars that can withstand higher working clutch pressure without the failure rate of the OEM unit .I know Beyond-red-line made mention of a CNC capacity but not much else came of the announcement or the doing of anything to benefit the Gen Coupe crowd (clutch cylinder).The clutch Cylinder we have in our cars like so many Items are pure junk in a effort to cut cost and gain profit at our expense .

 

[shorttrack]

For anyone else caring to improve / modify an existing different brand master clutch cylinder ,the piston O.D. diameter should be .623''to .625'' .Find a non OEM brand with this piston size .

 

[shorttrack]

.623'' to .625 piston cylinder /bore --- with a 1.250'' total stroke .from flange face to end is (3.075'' without rubber washer ) --- (3.500'' with rubber washer) and 5 inches total length .

 

[Red Raspberry]

Just what would be the advantage of a different clutch master cylinder? More fluid pushed to the slave cylinder?

 

[shorttrack]

Just what would be the advantage of a different clutch master cylinder? More fluid pushed to the slave cylinder?

No ,not more fluid .A different better designed master clutch cylinder would not flex and loose it ability to hold pressure .The internals of the GEN COUPE master clutch cylinder is made out of cheap plastic(from Hyundai cost $178.00 for a piece of junk/$78.00 from Rockauto .com)) with 2 O-rings within the master clutch cylinder body that tends to leak because the weak plastic piston .I would even say this, the cheap OEM clutch cylinder is a big part of why the 2nd Generation Gen Coupe suffers from shifting problems .The adjustable clutch rod can only take slack out but does not ,I repeat does compensate for lost hydraulic cylinder pressure and does not give more fluid than OEM clutch hydraulic system was designed for .The throw out bearing for a better word has roughly .060''-.070'' of travel to disengage the clutch ,any lost of pressure from the cheap OEM clutch master cylinder resulting in a minus only .010'' worth of travel in the slave cylinder will result in grinding ,gear hang up or worse ,destroyed synchronizer rings .We need a solution ,I hope we get it .The FRS and the 370Z crowd have the same problems as so does many other brands especially when going to higher clamping force aftermarket clutches with higher pressure plates, The venders that have addressed these brands problems have done so with better aftermarket master clutch cylinders (non plastic) .We need the same .I'm making an adapter to use either a 5/8 bore-1.300'' stroke Tilton or Wilwood on my Gen Coupe .

 

[shorttrack]

I do not know the fluid capacity of the Gen Coupe's throw out bearing ,but if it holds more than the current OEM master clutch cylinder can deliver and more ''lift'' could be had with a larger aftermarket clutch cylinder with a .700 '' - .750'' cylinder bore,that would be beneficial provided that the stroke could be adjusted correctly to provide the proper volume to the clutch slave cylinder so as not to cause the seal to blow out and leak .

 

[shorttrack]

So I cut the master cylinder in half since it was messed up anyway. Here are some of the pictures I got, also the O-ring for the hard line fitting to master clutch cylinder discharge outlet was cut .

 

[shorttrack]

Ordered a new Gen Coupe clutch cylinder from rock auto.com for $82.00 shipped (OEM cost about $180.00) , my Gen is still under warranty but I will not waste my time with these idiots at the Houston Hyundai dealership .But I'm thinking about using a 1984-85 Mazda RX 7 master clutch cylinder .All is needed is to drill the 2 holes through the firewall in the correct location ,change the hard line fitting to fit the Mazda cylinder outlet fitting and done .I had a 13B bridge ported Rotary that I ran 10.60's in the 1/4 and these Mazda OEM clutch master cylinders never failed in over 7 years of hard abuse .They are .625 bore and same stroke and are rebuildable for $20.00 . IF ANYONE NEEDS THIS NEW CLUTCH CYLINDER I ORDERED ,LET ME BEFORE I SEND BACK .It has not arrived yet .

 

[johnzm]

u kidding me its really a plastic clutch master?

theres no point in putting an adjustable rod on a plastic master you are just adjusting the rod to compensate for all the bending plastic everywhere else.

i guess with this you want to be around the same volume as the stock one otherwise there is a possibility of popping the TO apart when you are at full stroke.

i havent bothered looking at any of this hardware yet, but it would be pretty sweet to find a bolton OEM solution from another car. much cheaper route than a tilton id guess too.

 

[shorttrack]

u kidding me its really a plastic clutch master?

theres no point in putting an adjustable rod on a plastic master you are just adjusting the rod to compensate for all the bending plastic everywhere else.

i guess with this you want to be around the same volume as the stock one otherwise there is a possibility of popping the TO apart when you are at full stroke.

i havent bothered looking at any of this hardware yet, but it would be pretty sweet to find a bolton OEM solution from another car. much cheaper route than a tilton id guess too.

That is what I am doing, installing a Mazda RX-7 clutch master cylinder this weekend .Problem solved .

 

[shorttrack]

u kidding me its really a plastic clutch master?

theres no point in putting an adjustable rod on a plastic master you are just adjusting the rod to compensate for all the bending plastic everywhere else.

i guess with this you want to be around the same volume as the stock one otherwise there is a possibility of popping the TO apart when you are at full stroke.

i havent bothered looking at any of this hardware yet, but it would be pretty sweet to find a bolton OEM solution from another car. much cheaper route than a tilton id guess too.

Purchased the 84'/85' Mazda GSL-SE RX 7 clutch cylinder(autozone $40.00) and another style adjustable clutch rod (that will need minor modification) that I will be installing Fri/Sat .The master cylinder shares the same stroke and cylinder bore as the Gen Coupe's master clutch cylinder .The 2 Mazda cylinder stud will line up ,I already have the male fitting

 

[johnzm]

Purchased the 84'/85' Mazda GSL-SE RX 7 clutch cylinder(autozone $40.00) and another style adjustable clutch rod (that will need minor modification) that I will be installing Fri/Sat .The master cylinder shares the same stroke and cylinder bore as the Gen Coupe's master clutch cylinder .The 2 Mazda cylinder stud will line up ,I already have the male fitting

take some pictures of the install. i would upgrade pretty quickly to a metal one if it were a bolt in process. anything to solve this clunky trans lol

 

[Red Raspberry]

Long time ago I removed the white plastic pad that the pedal bottoms out on to get more stroke. All it did is end up breaking the clutch ignition switch.

 

[shorttrack]

take some pictures of the install. i would upgrade pretty quickly to a metal one if it were a bolt in process. anything to solve this clunky trans lol

I should have it all done this weekend ,I will post pic's .

 

[shorttrack]

Long time ago I removed the white plastic pad that the pedal bottoms out on to get more stroke. All it did is end up breaking the clutch ignition switch.

Red ,what I did was installed my adj clutch rod and left those tabs in place just for that very same reason .This RX 7 clutch cylinder has the same stroke and cylinder diameter bore so it will not be a problem after the install is completed this weekend .It will just seal better and have no flex .The flex is the plastic piston itself .Also the conversion will get rid of the clutch hard line O-ring to plastic fit at the clutch cylinder discharge port .My O-ring had a nick on it (could been why it would not build consistent pressure).

 

[shorttrack]

As I stated ,the Gen Coupe is good platform that is bogged down by terrible execution ,I will be addressing my engine the same way after all odds and ends are done .No engine swap for me .Fixing what I know is wrong and going to the track to have a little fun .

 

[shorttrack]

Install is done .The clutch hydraulics are finally working consistently but nt enough travel ,the RX7 cylinder is 1.100 inches of travel and our Gen Coupe has up to1.250 inches of total travel .The install was not that bad but I must say it would be advisable to spend the extra $30.00 on a Tilton or Wilwood clutch cylinder with a remote reservoir and the extra travel,say about 1.400 inches with a.700'' piston bore.The most difficult part was drilling the 2 holes (that sounds NASTY HA-HA!!) .The bottom hole I used a 12 inch long drill bit from inside the car and a 90 degree air dill from engine compartment .When I get a chance I will post pic's .The clutch seems fine I just don't have enough travel with RX7 cylinder .Took about 4 hours to complete .

 

[Red Raspberry]

FWIW BMW and VW also used this trans in some of their cars though it was the original ZF transmission and not a copy like Hyundai uses.

Though I have not seen their concentric slave cylinders there is one made by Sachs listed for it and it looks just like the Hyundai version. But don't know if it is more reliable or if they have a master cylinder that would swap in.

Here is the CSC by SACHs for the Gen Coupe. They may be the OEM supplier.

https://webcat.zf.com/?SPR=4

 

[johnzm]

i hope we can figure out a replacement that is not a 4 hour job to install. thats too laborious for this job when there is very likely a bolt in solution from hyundai (sonata ect) or their oem supplier.

can anyone confirm the following measurements? from my previous experience, my assumption is that the rod on the wilwood can easily be swapped to the SFR piece without too much hassle before installation

 

[shorttrack]

i hope we can figure out a replacement that is not a 4 hour job to install. thats too laborious for this job when there is very likely a bolt in solution from hyundai (sonata ect) or their oem supplier.

can anyone confirm the following measurements? from my previous experience, my assumption is that the rod on the wilwood can easily be swapped to the SFR piece without too much hassle before installation

That is the selection I'll most likely going with next or a Tilton(Summit Racing or Jegs but with a .700'' cylinder bore and 1.400 inches of travel .Took me 4 hours from start to finish .It is not as hard as it appears .The RX7 cylinder does not move enough fluid .