How to know when clutch master cylinder is going

**JehalinTA** · 06-17-2009, 04:36 PM

Just wondering if anyone knows the symptoms of a master cylinder going out .Thanks

**Wesman** · 06-17-2009, 07:19 PM

Clutch pedal feels mushly, clutch not releasing, possible external fluid leaks.

**JehalinTA** · 06-18-2009, 04:59 AM

What if there is pressure... but the pedal does not go down smooth, rather makes a clicking sound?

***SMWS6TA*** · 06-18-2009, 07:37 AM

Glad someone posted this question. Today, my clutch is mushy, sometimes doesn't come back up.

My questions are these:

1) To replace both Master and Slave cylinders will I have to drop the transmission?

2) How difficult of a a job? Something that can be done in home garage? or will I need a lift and other tools not usually in a home garage?

**Wesman** · 06-18-2009, 07:53 AM

Originally Posted by SMWS6TA

Glad someone posted this question. Today, my clutch is mushy, sometimes doesn't come back up.

My questions are these:

1) To replace both Master and Slave cylinders will I have to drop the transmission?

2) How difficult of a a job? Something that can be done in home garage? or will I need a lift and other tools not usually in a home garage?

Master can be changed with the car on the ground. You'll just need to crawl under and disconnect the quick-connect fitting to the slave cylinder.

To replace the slave, you need to pull the transmission. The slave cylinder is bolted to the adaptor plate on the front of the trans, it slides over the input shaft.

Its not all that difficult, its just time consuming. The worst part is muscling the trans in and out, its quite heavy at around 130lbs. The top right bolt that connect the trans to the bellhousing is also a pain to get to, as its very close to the body of the car. You'll need a long extension and a swivel adaptor to get at it.

I did mine as home, but I also have a lift, which made it much easier. However, as long as you have the car high enough in the air (all 4 wheels on ramps probably) then you should be able to tacke the job.

***SMWS6TA*** · 06-18-2009, 01:51 PM

Originally Posted by Wesman

Master can be changed with the car on the ground. You'll just need to crawl under and disconnect the quick-connect fitting to the slave cylinder.

To replace the slave, you need to pull the transmission. The slave cylinder is bolted to the adaptor plate on the front of the trans, it slides over the input shaft.

Its not all that difficult, its just time consuming. The worst part is muscling the trans in and out, its quite heavy at around 130lbs. The top right bolt that connect the trans to the bellhousing is also a pain to get to, as its very close to the body of the car. You'll need a long extension and a swivel adaptor to get at it.

I did mine as home, but I also have a lift, which made it much easier. However, as long as you have the car high enough in the air (all 4 wheels on ramps probably) then you should be able to tacke the job.

I'm so jealous!!

**Wesman** · 06-18-2009, 08:21 PM

Originally Posted by SMWS6TA

I'm so jealous!!

It does make it nice to work on things

***SMWS6TA*** · 06-19-2009, 07:56 AM

One more question: When you swap out the two, how do you replace the fluid?

It will be the first time I try to replace his stuff so of course I have to ask all the stupid questions.

Also, to the OP, sorry for jacking your thread.

**Cutlass** · 06-19-2009, 12:20 PM

its just like bleeding brake fluid. top off the master and open the bleeder.
Refer to the sticky "Sticky Clutch pedal write-up"
http://www.ls1.com/forums/showthread.php?t=55824.
The forth bold subject down describes it.

**JehalinTA** · 06-19-2009, 12:50 PM

from my experience bleeding the clutch manually is a pain in the butt and was practically impossible to do due to the amount of air that got into the system. The easiest, one man bleed job, is to get a vac pump or brake bleed pump. I was too cheap to buy one then when manual was taking too long I got one and bled it in less than 10mins.

**Wesman** · 06-19-2009, 08:51 PM

Originally Posted by JehalinTA

from my experience bleeding the clutch manually is a pain in the butt and was practically impossible to do due to the amount of air that got into the system. The easiest, one man bleed job, is to get a vac pump or brake bleed pump. I was too cheap to buy one then when manual was taking too long I got one and bled it in less than 10mins.

I just bench bled my master cylinder, installed the entire system, and then bled it manually. Within 15 minutes I had all the air out and a nice firm pedal.

**silverjess** · 06-22-2009, 04:24 PM

Whats the average time span it takes to change the master?

**Wesman** · 06-23-2009, 07:56 AM

Originally Posted by silverjess

Whats the average time span it takes to change the master?

It wouldn't be bad at all if the master wasn't a complete bitch to get to. Its under the brake booster where you can't see it, so you basically have to go by feel. So when you're trying to install the new one, you're basically trying to get the studs through the holes by feel, nothing else. This can prove to be very difficult and frustrating. If you're lucky, you'll get it on the first few tries and have the job done in about an hour or slighlty more. If you jhave trouble getting the new one in, you could be there a while.

**Danger731** · 06-23-2009, 09:06 AM

If your master is going out it is usually the seals which will make your fluid black. Look at your fluid, if the color is still good the master is prolly good as well.

**JehalinTA** · 06-23-2009, 04:38 PM

Originally Posted by Danger731

If your master is going out it is usually the seals which will make your fluid black. Look at your fluid, if the color is still good the master is prolly good as well.

very good... I installed a clutch, slave, and fly wheel...about 1,000 miles ago.. replaced the fluid and the fluid is black already. Is this a sure indicator of my MC going? I really think my master cyl. is going out based on the way the clutch feels and acts.
My next question then where can I get a good quality master that wont cost me as much as the McLeod adjustable one.

**Wesman** · 06-23-2009, 05:12 PM

Originally Posted by JehalinTA

very good... I installed a clutch, slave, and fly wheel...about 1,000 miles ago.. replaced the fluid and the fluid is black already. Is this a sure indicator of my MC going? I really think my master cyl. is going out based on the way the clutch feels and acts.
My next question then where can I get a good quality master that wont cost me as much as the McLeod adjustable one.

Not necessarily.

There are many things that can turn the fluid black. Contaminants in the fluid, as well as rubber from the inside of the clutch line can darken the fluid.

I wouldn't condemn a master cylinder based purely on fluid color alone.

What are the other symptoms??

**Danger731** · 06-23-2009, 08:48 PM

Master is shot

**JehalinTA** · 06-24-2009, 04:24 AM

Originally Posted by Wesman

Not necessarily.

There are many things that can turn the fluid black. Contaminants in the fluid, as well as rubber from the inside of the clutch line can darken the fluid.

I wouldn't condemn a master cylinder based purely on fluid color alone.

What are the other symptoms??

I agree... however, the fluid being black is a little unusual as I have babied the clutch and drained the entire system and added new fluid during the clutch/ slave install...then few hundred miles later the fluid is as black as can be. Aside from that when I push the clutch pedal down the engagement is not smooth. Rather, it makes a clicking/ popping sound?? hard to describe. Also about half of the pedal being pushed down has no response. The clutch does not begin to engage until after the half way point. I am not sure if this is directly related to the MC but a possibility. I am just worried about prematurely wearing a 700.00 clutch. Thanks for the input