Welcome to Ultimate Subaru Message Board, my lurker friend!
|Welcome to Ultimate Subaru Message Board, an unparalleled Subaru community full of the greatest Subaru gurus and modders on the planet! We offer technical information and discussion about all things Subaru, the best and most popular all wheel drive vehicles ever created.
We offer all this information for free to everyone, even lurkers like you! All we ask in return is that you sign up and give back some of what you get out - without our awesome registered users none of this would be possible! Plus, you get way more great stuff as a member! Lurk to lose, participate to WIN*!
* The joy of participation and being generally awesome constitutes winning
** Not an actual guarantee, but seriously, you probably won't regret it!
Serving the Subaru Community since May 18th, 1998!
Heat Wave & Clutch Pedal Goes Soft
Posted 10 June 2008 - 05:35 PM
We've been suffering through a heat wave on the east coast for the past week with temperatures in the mid- to high 90s. After about 20 minutes of city driving this afternoon, my clutch pedal went soft, disengaging the clutch at the bottom 1/3 of travel and, at certain points, sticking to the floor. After the car cooled down a bit, pedal action went back to normal.
I didn't feel like getting stuck in bumper to bumper, mid-summer metro traffic so I rebuilt the slave cylinder with a Subaru kit. The cylinder bore surfaces looked perfect, but the old piston seal showed a bit of wear.
I would have thought that extremely cold conditions leading to shrinking seals would be more likely to cause this type of failure.
For those who experience the same problem, here are the pertinent links that have been posted on the site.
There is a discrepancy between the Factory Service Manual (FSM) and the Endwrench links for the torque value on the banjo bolt --
13 +/- 2.2 ft-lbs. and 27 +/-2 ft-lbs., respectively.
And according to the FSM, the mounting bolts for the slave cylinder should be torqued to 27.2 +/-2.2 ft.-lbs.
Posted 11 June 2008 - 02:52 PM
Out of curiosity, what is the "banjo" bolt?
Posted 12 June 2008 - 09:09 AM
Posted 12 June 2008 - 02:17 PM
ANy temp change can cause an issue with a part, because metal expands with heat, and it doesnt take much of a leak to get what you saw.
Good point, Nipper -- and high heat and humidity resulting in a decrease in brake fluid viscosity and more water vapor to be absorbed only adds to the problem.
I was thinking of a recall on brake master cylinders, where similar hydraulic symptons would appear in extreme cold.
Whereas the Endwrench links suggest replacing the slave cylinder, hose, and washers, I had only the slave cylinder repair kit on hand and reused the old washers, which did the trick. Pedal feel is firmer and more consistent.
The repair kit comes with a new pistion & seal, piston spring, rubber boot, and bleed valve cap. After you've removed the slave cylinder, it takes only another 5 minutes to clean the cylinder & install the new parts from the kit.
Posted 08 July 2008 - 08:40 AM
Posted 08 July 2008 - 05:26 PM
At 1stsubaruparts.com, the rebuild kit is 12.88 plus shipping. The cylinder doesn't really wear out, and the kit comes with all the parts that do. I ordered it along with some other parts a while back, hence had it waiting for the day to come, and sure enough, it did.
Posted 02 August 2008 - 07:58 AM
Bleeding the sysytem several times did not fix the issue, and as far as I could see, there was no air in the system nor were there any fluid leaks. But rather than deal with the continued agitation, I decided to renew the entire hydraulic system and replaced the clutch hose and master cylinder.
The old hose looked fine, and it's hard to imagine how this alone, unless ruptured, could have such drastic effects. I see in the TSB that the WRX is exempted from hose replacement, which must only mean that they come equipped with steel braided ones.
Posted 02 August 2008 - 08:13 AM
Posted 05 August 2008 - 08:49 AM
I looked for a rebuild kit for the Master Cylinder, but there were none to be found. When I took the old one apart, the aluminum cylinder bores were perfect. Though it's a softer metal as compared to the cast iron slave cylinder, I can't imagine the rubber seals can cause all that much cylinder wear.
Anybody know a supplier for just the piston seals? They seem like pretty standard parts for a 5/8" bore.
One nice feature on the new master cylinder was a bleeder valve on the front, which makes bleeding the system a whole lot easier.
0 user(s) are reading this topic
0 members, 0 guests, 0 anonymous users