Clutch Master Cylinder Replacement

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Hopefully this will put to rest my clutch pedal saga. I have replaced the clutch pedal return spring and now I have found a leak in the clutch master cylinder. Because of this I have had to adjust the pedal so I get more pressure to the master cylinder and that has the pedal way out.

Update. The leak is there because the brake fluid tube from the brake fluid reservoir is dangling next to the master cylinder. Upon closer inspection it appears the grommet that holds that tube is ripped and that probably allowed the tube to work its way out. So do I try and replace the grommet or swap the entire master cylinder. I decided to do the master cylinder swap. I didn’t know it something else may be damaged or compromised because it’s been running low on fluid or if has become contaminated from foreign substances. I’d hate to replace the grommet and then have to swap the entire unit down the road.

The swap:

The swap was pretty straightforward. There are 2 bolts on the pedal box holding the master cylinder in and two hoses on the top. One going to the brake fluid reservoir that’s a push in style and one screw in tube that goes to the slave cylinder. The tricky part is getting to all this with the limited space. I have a 76 so there was a box that was for the emissions check light that came on ever certain amount of miles. That box which was disconnected was still there. I removed it to get it out of the way. It’s where the 2 piece transmission cable is joined but if you are up on the blog, I replaced the 2 piece cable with a longer 1 piece in prep tearoom of the 5 speed swap and because the 2 piece cable got damaged by a gas can in the road.  Most of the work was done from under the car. Once I removed the old one I was faced with the task of how to get the the fluid pipe into the new master cylinder. Most people said this was the most difficult part. It’s a simple press in procedure but you have to get enough pressure to fully insert it or it will come out.  I tried from above And below and I just didn’t have enough room to make it work. My solution was to pull the tube out of the car and insert the hose into the master cylinder then snake the master cylinder with the hose attached into the pedal box. That was simple and fast. Once that was back in the trick was to get the bolts back into place. I used a pair of vise grips to hold the bolt in place in the pedal box while tightening the bolt from under the car. Worked out pretty well and was pretty quick and easy. I then attached the master cylinder to the clutch cable. Making sure the distance between the bolt that attaches to the pedal and the body of the master cylinder was 100mm. I used new bushings for the pedal that I got last week and the clutch pedal return spring was also just replaced.once that was done the pedal was at the correct distance from the floor and had a nice resistance to it. Now for the final part. Bleeding the system. This was the easiest part. Apparently the system was designed to gravity bleed. So unscrew the bleed valve on the slave cylinder them fill the brake fluid reservoir and wait until all the bubbles are out and fluid is coming out of the bleed valve then tighten the bleed valve. I buttoned it all back up and took it for a test drive and all is done!!!  Great result. I now have great clutch pedal feel and travel. No leaks and smooth clutch operation.  All in all it was about a 2 hour job without rushing. After about a day of aggressive driving the fun is back!!!

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