How to - Clutch Bleed

[SmallSoldier]

Gents,

I have been researching the forum for a while, but haven't had much success finding a "how-to" for bleeding the clutch (which I hope will fix the issue with my car)

Around a month ago while driving home, out of nowhere, my clutch pedal went to the floor at a red light, no pressure whatsoever and couldn't engage any gear... Turn off the car, place it in neutral "pump the clutch" several times (between 5-10 times) and pressure would be build enough that I could keep on driving

The car started showing the same problem after been parked for a week or so, but pumping the clutch would allow me to get going and I would have to occasionally do it at a red light

But the problem has exacerbated to the point that the loss of pressure on the clutch is happening actually while driving (which won't allow me to even change gears)

After speaking with a couple of friends, they seem to believe that clutch fluid may have gone low (probably a leak) and the lower it got, the more air that entered the system and created this problem... I have tried to find someone local (I live in SLC, UT) and the only person that has been recommended to work on the Cobra is unluckily booked for a little more than a month

Any chance anyone can point me to a how-to for bleeding my clutch or that could tell me how to do it here? I haven't jacked the car yet, but I haven't even been able to find the valve to bleed it, the reservoir seems to be inside of the fender, behind the brake reservoir which is a tricky location to even see anything from the hood (I will try to jack it up this weekend)

Thanks in advance for any help... Really appreciate it!

[HSC-ZL1]

Depending on the type of unit you have. The Mcleod trans mount units can go away just with dust contamination their tech line recommended bleeding unit every other oil change. there should be a bleed line coming out of the bell housing if this is your style. A vacu-bleed with careful attention to fluid level until clean fluid is seen in vacu-bleeder. Most trans mount units should be similar. Slave cylinder units outside bell housing are a different animal. Bleeding might help but slave cylinder could be failing.

[SmallSoldier]

Thank you! I bought the car used and not sure which type I have... The car was build in 2002... I believe I have identify the reservoir for Master Clutch Cylinder, any idea on where the slave might be located?

Thanks again

[jhv48]

Have you checked the fluid reservoir to see if it's full?

Is there fluid leaking from the slave under the car?

If you are having to pump the pedal to build up pressure, either the master or slave probably need to be replaced, as fluid is leaking past the seals.

[SmallSoldier]

Originally Posted by jhv48

Have you checked the fluid reservoir to see if it's full?

Is there fluid leaking from the slave under the car?

If you are having to pump the pedal to build up pressure, either the master or slave probably need to be replaced, as fluid is leaking past the seals.

I will purchase a new master and slave and replace them for some piece of mind... This is going to be a very silly question, but where is the slave supposed to be located

I haven't checked if there is fluid in the reservoir, there doesn't seem to be a way to check?

Shall I buy both from Wilwood? From what I read in the forum, it seems to be what most do

I apologize for the stupid questions... Finally bought my dream car and just trying to learn more about it (and try to fix it if the difficulty level isn't too high)

Thanks for the questions! As soon as I get back in the states, I will jack up the car and check for any leaks

[jhv48]

Don't start replacing things until you figure out which one needs attention. Could be you just need to fill up the reservoir and bleed the system.

Not sure where backdraft locates their clutch reservoir. It's either on the firewall inside the engine compartment or to the fender side of the steering column under the left front fender inside the engine compartment. Start there.

[DanEC]

There are typically two types of slave cylinders - external to the bell housing and internal to the bell housing. You need to get under the car and see if you can determine what you have. For the external slave you should typically see a small cylinder bolted to the rear of the engine with a rod extending back to a fork sticking out from the driver side of the bell housing. The internal type slave will not have a fork - there will be a hydraulic line extending into the bell housing. The internal slave is cylindrical and fits over the transmission input shaft. Hope that you have the external type as the transmission has to come out to replace the internal type slave.

I would try to determine who your existing master and slave cylinder are made by and their piston size or model number. The safest thing is to replace them in kind since the cylinder dia (size) will have already been figured out by the manufacturer.

And as a lesson learned (from someone who really shouldn't have had to learn it) the slave cylinder needs to be rotated in it's mount to where the bleeder valve is at the top (high point). Otherwise you will get the air out of the system.

[Trueoo7]

I agree, the master cylinder is in a tough spot, but you can screw off the top of the cylinder and shine a flashlight into a mirror (positioned just right) to see into the reservoir. Or you could just dip your finger in and feel for the level. It should be just below the rim but no more than a 1/4" or so. Also check inside the car in the drivers footwell on the rug. If you have carpet right up to the pedals, it could be dripping and absorbed by the rug so you wouldn't notice it right off. Leave a paper towel or look on the pedal lever for wetness or drips. That's how mine started leaking. Following the hydraulic line that comes out of the clutch master cylinder down to the slave is the easiest way to find it. Depending on the manufacture number of the car it may pass into the footwell and back out by the tranny. That was the improvement to keep it
away from the heat of the headers. Check the connections too for wetness or leaks.
When you find the leak then we can go from there as far as bleeding it. I'll have to look in my paperwork but I replaced my master cylinder with a Girling Brand and it was an exact fit. I also bought the exact slave cylinder that was on the car, on line, again I'll have to look at paperwork. You could also take some pictures and post so it will be easier to identify the units.

[SmallSoldier]

Thanks a lot for all the advices... I feel a little embarrassed for asking this silly questions and I appreciate all the feedback and kind responses

I promise to post some pics of the car too as soon as possible... The car was build in 2002 and has a built 351W with a Tremec 5 speed transmission (not sure on the model)... It has 39k miles... It's silver with black stripes

My plan of attack for the weekend will be to:

A) Check the fluid level (use finger method, seems the easiest)... The reservoir is located on the driver's side, behind the break reservoir (metal with a black cap on top)... Hopefully that's the one... If fluid is low (which, if I have a leak, most probably is), will top it off... Any brand/type anyone recommends? I read that is better to look for a dot 3 than a dot 5?

B) Check in the footwell (I do have carpet) for any signs of fluid

C) Put the car on jack stands and try to follow the line to the slave cylinder (hopefully I will find it!)... Is there an specific location to place the jack stands that is recommended?

D) Try to clean the line as good as possible to allow me to see if there are any leaks

D) Ask my wife to get in the car and press the clutch pedal (after I have topped it off) and check for leaks

E) Take as many pictures as possible and come back to the forum for advice on bleeding the clutch if there are no visible leaks in the lines that need to be fixed/replaced

Sounds like a decent plan?

I guess the hardest part will be to find out the model of the master cylinder and slave cylinder if I need to replace them

Thanks again!

[Gun Doc]

SSoldier,

You most likely have a Wilwood slave; it’s located on the driver’s side aft of the bell housing. Mine started leaking early on and I replaced it with a custom mount and a slave from what I believe is a Mazda. No leaks since I did that about six years ago.

They are fairly easy to bleed with a helper to depress the clutch pedal. You can You Tube it!!

Gun Doc

[Gun Doc]

SSoldier,

You most likely have a Wilwood slave; it’s located on the driver’s side aft of the bell housing. Mine started leaking early on and I replaced it with a custom mount and a slave from what I believe is a Mazda. No leaks since I did that about six years ago.

They are fairly easy to bleed with a helper to depress the clutch pedal. You can You Tube it!!

Gun Doc

[cbreez]

Many threads on this...99% of the time the slave is leaking. Leave the master alone and replace the slave with whatever it had on it and live with it till the next time. I find it's easier to refill master from the passenger side, reaching over with a shot glass of fluid.
You can easily bleed by yourself...first drip bleed, then close bleeder, and then pump the heck out of it. (30) This is a very vertical system and most air bubbles will rise to the mc and dissipate. Good Luck.

BTW, brand is not that important, it's just a bad heat problem that ruins the fluid, then the slaves.

[SmallSoldier]

Thanks again... I will work on this and update everyone

[DanEC]

Originally Posted by cbreez

BTW, brand is not that important, it's just a bad heat problem that ruins the fluid, then the slaves.

Also alignment - if the rod is angled to meet the fork the piston is probably scraping on the bore and wearing it. The fork will always move the rod in a slight arc so you can't achieve perfect alignment - but try to adjust it to the extent the mount provides - to stroke as straight as possible.

[6t8stang]

I find it easiest to access the clutch master cylinder leaning over the driver's side fender, (head almost upside down). I bought the smallest bottle of fluid available (bottle is only about 4" tall). This allows you to reach behind the brake master, unscrew the cap and pour from the little bottle. Careful not to get fluid on any painted surfaces...

I agree your slave is probably leaking. If Wilwood, they sell rebuild kits to replace the seals. Now would be a good time to switch to a high temp fluid and flush the system. You'll probably find the fluid is pretty dark.

Being built in 2002, you may not have a heat shield beneath the two master cylinders - definitely helps having one. Also look at how the hydraulic line is routed from the master to the slave - might be room for heat shielding as well as these are generally close to the headers.

[SmallSoldier]

Originally Posted by 6t8stang

I find it easiest to access the clutch master cylinder leaning over the driver's side fender, (head almost upside down). I bought the smallest bottle of fluid available (bottle is only about 4" tall). This allows you to reach behind the brake master, unscrew the cap and pour from the little bottle. Careful not to get fluid on any painted surfaces...

I agree your slave is probably leaking. If Wilwood, they sell rebuild kits to replace the seals. Now would be a good time to switch to a high temp fluid and flush the system. You'll probably find the fluid is pretty dark.

Being built in 2002, you may not have a heat shield beneath the two master cylinders - definitely helps having one. Also look at how the hydraulic line is routed from the master to the slave - might be room for heat shielding as well as these are generally close to the headers.

Thank you! I will take pictures of everything I can find... I always wanted to build a Cobra, but as all of you can tell from my questions, I don't have the knowledge to pull it off... The opportunity came to buy one used at a good price and couldn't let it get away

Part of the reason to buy a Cobra was also to be able to work/wrench on it... It will be a very steep learning curve for me and tons of questions that I will need to ask... Luckily, this forum seems to be full of people eager to help/teach and I'm going through as many threads as possible to start learning (I promise I won't bring threads back from the dead)

[Mark Brye]

I should also add that on my older BDR, I can only get three good pumps of the clutch pedal before master is sucking air. So once you fill master, and start bleeding, make sure to check the fluid level before the fourth pump.

[jimbo01]

The external fluid reservoir Backdraft sells would allow you to fill the clutch reservoir easily but would require you to change the clutch master cylinder I have #832 and I am changing the reservoir to a billet reservoir and an fittings to the clutch master and the slave. I will be using an 3 hose to the clutch master and an 4 to the slave. Not a difficult job but you need some mechanical abilities and knowledge to get it done correctly. I also changed the bracket that holds the slave cylinder in place. The one Backdraft sells will bend under clutch operation. I had one made from 4130 aircraft steel. It want bend.

[vref120]

I had issues early on with my car and my problem was the master cylinder. Pedel would get soft sometimes. At the end when I had enough, almost had to pump the clutch to get it to build pressure. Checked all the areas everyone else mentioned. Changed the slave and did not make any difference. Tried bleeding multiple times, but no success. I will say, bleeding the clutch is not fun. Tiny reservoir and hard to get too. I went to a beauty supply shop and bought a plastic hair color bottle with a 90 degree tip. This made refilling much easier. You still have to be pretty limber to reach it, but this helped. Bleed it off the slave, but make sure you don't push it more than 4 times like someone else mentioned. It will drain quickly. In the end, my master cylinder went bad. I took the side gill off to access it. It's held on by 3 bolts and one is threw the firewall next to the clutch pedal. Yours might not be the same, but removing it will make your life easier if you have too. I bought
My slave and master cylinder both from summit.

[SmallSoldier]

Wanted to update and thank everyone... I went to bleeding the clutch and is much better now! The reservoir was empty, filled it up and used one of those "One Man Bleeding" bottles that are sold in Autozone

I believe I still need to bleed it a little more, but at least I don't have to pump it anymore while driving it... Small victory!

I don't know if I should start another thread, but need more advice... The car died on me about 20 yards from home... Diagnosed it as best as I could and found out that it was because I didn't had spark... Checked the coil and it was working, when I took the cable that goes from the coil to the distributor cap, it was rusty inside... Cleaned it up and it fired again

I need to buy a new distributor cap, new spark plug wires and would like to buy new spark plugs... Any recommendations on what I should buy?

I have tried to post pictures of my car, with no luck... Will keep on trying

Thank you!