Clutch master cylinder pushrod

slowolej · Posted: Sun Jun 22, 2008 1:11 pm Post subject: Clutch master cylinder pushrod

My 89 Sunbird has a 2 piece master cylinder pushrod which is currently bent. The rod is made of two pieces; a roughly 1/4" solid rod and a roughly 5/16" OD hollow end which is slid over the 1/4" rod and crimped. The rod has bent where the two halves meet. I'd like to replace this with something stronger and I'm hoping someone might have an answer which can save me a little time.

Has anyone replaced the stock pushrod with an "upgraded" part? What did you use?

Anyone know of a Heim joint which will fit the pin on the clutch pedal?

One plan I'm considering is using a modified brake pushrod. The eye which attaches to the brake pedal is roughly 5/8" rather than the smaller diameter used on the clutch pedal. Anyone have thoughts about using a bronze flange bushing on the clutch pedal pin? Any other possibilities?

TIA

barrok69

slowolej · Posted: Mon Jun 23, 2008 11:26 am Post subject:

Not sure why this got moved to repair. The question is about stronger/better/faster type modifications, not stock replacement. I've got a good used stock part should I choose to go that route.

barrok69 · Posted: Mon Jun 23, 2008 12:02 pm Post subject:

slowolej · Posted: Tue Jun 24, 2008 11:37 am Post subject:

I pulled the pushrod off a 92 Z24 parts car last night. What a different piece that is. My Sunbird cylinder and pushrod is the same as what's found on Isuzu equipped cars, but the Z24 system uses an 8mm diameter threaded rod on the m/cyl side and a very heavy duty eye on the clutch pedal end. The Z24 rod is shorter and the m/cyl end "ball" is much larger than the 'Bird part. I measured the pin on the pedal and came up with .429" which is a little shy of 11 mm. I'm still looking for parts to make this work.

slowolej · Posted: Thu Jun 26, 2008 5:56 am Post subject:

I now have a newer, faster, better pushrod. I ended up with a stainless steel eye made from 3/8" diameter rod. I used a rotary file to open the eye slightly and pressed in a flange bearing with a 7/16" ID and a 1 1/8" OD. The eye measured 8" overall length so I'll need to trim the length slightly and grind a ball or point on the master cylinder end. The next steps are to devise a method to retain the bearing on the clutch pedal and to remove the old pushrod from the master cylinder.

To remove the pushrod I have a piece of steel tubing in which I have cut a slot from one end to the other. The tube gets slipped over the stock pushrod then tapped toward the master cylinder until it presses on the three spring steel retaining "fingers" in the end of the cylinder. This releases the rod. It works kind of like releasing the quick connect fittings on a Ford fuel line. Works good on the bench, but we'll see how it goes when I'm in the car working under the dash.

I'm hoping I can drill a hole in the clutch pedal arm for a cotter pin to hold the new pushrod. Otherwise, maybe I can use a mini tubing cutter to make a groove for an E clip or snap ring.

I'm going to try and take some pictures of all this for future reference.

barrok69 · Posted: Thu Jun 26, 2008 9:57 am Post subject:

slowolej · Posted: Fri Jun 27, 2008 6:27 am Post subject:

Thanks. I'll keep that in mind. Right now I'm trying to do everything without removing the pedal. The special tool worked perfectly and the new pushrod installs without a problem. It actually looks like the factory groove for the plastic clip is going to be just right for an E-clip.

slowolej · Posted: Fri Jul 04, 2008 9:34 am Post subject:

Ok, as promised, some pictures.

The picture of 4 pushrods shows, from left to right, the bent pushrod from my 89 Sunbird, a stock replacement rod from another car with a plastic clutch master cylinder (these are the most common type), a stock pushrod from a 93 Z24 with aluminum master cylinder and integral slave (nice, but too short), and my homemade pushrod before cutting to length and grinding. The new rod is now installed and fits well. The 7/16" ID ball bearing fits snugly over the clutch pedal pin. I used an E clip to retain the assembly by fitting it into the groove on the pedal pin. If you look at the bearing you'll see the flange which keeps the rod from sliding off the bearing in one direction. The pedal keeps the rod from moving in the other direction. It feels very solid now and I think there's little chance of bending it.

Removing the pushrod from the master cylinder takes some practice. I've included a picture of the high tech tool I used. The real trick is to get the tool slipped down into the master cylinder far enough to release the three locking tabs so the rod can be pulled out. The arrows in the third picture point out the locking tabs. I was able to remove mine while the master was still installed, but I practiced on the bench with another one first. I had to use small channel locks and I cut the tool so when it had fully pressed in the clips, the opposite end just showed the point where the two pushrod halves are joined. This way I wasn't guessing whether or not I had the tool installed far enough. The threads on the new pushrod work with the locking tabe to keep the rod in the clutch master cyl, but if I ever need to remove it again I can unscrew it instead of fighting those clips.

I still think this, or something with this information, should be in the performance section. There are no other posts I've found showing any type of "high performance" pushrod solution to use with a stock master cylinder.

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