Wheel cylinder effects

[GrndNatnl]

Is there any difference in pedal feel, effort, or travel when using the S-10 wheel cylinders with the larger bore?

I just did this switch (after rupturing a cylinder on one side somehow). I switched to the larger bore S-10 cylinders, and for some reason I cannot get back the same high pedal that I had before. I'd like to think I still just have air in the system somewhere, and should bleed them a little more. Reason being is that the braking force isnt all that great either. They wont even lock on wet road.

But curiosity led me to ask if the larger cyls make a noticable pedal difference, being that they compress more fluid within a slightly larger volume.

 

[MaxVO2]

It's been my experience that Powermaster setups are less forgiving than a more typical vacuum setup with respect to having clean fluid, and proper bleeding procedure.

I just installed S-10 wheel cylinders a few weeks back as well on my 87 GN. Anytime I open up the brake system, I always bleed out all 4 wheels to make sure I get all the air out. In addition, I depress the little button on the proportioning valve while the brakes are being bled (the one with the rubber cover on it, on the bottom of the valve). I use a small c-clamp with a small ball bearing or whatever I have lying around to keep it depressed while I work.

Anyway, I've gotten in the habit of changing all of the brake fluid about once a year or so, and making sure the master cyclinder reservoir is spotless before putting in new fluid (I drain the reservoir dry after having pumped the pedal with the cap on like 20 times, clean it all out with the Mity-Vac, and put fresh fluid in before bleeding everything..). I use either a Mityvac or a one-man bleeder setup made by the Lisle company. It has a magnet on the bottle to stick it on the frame above the caliper or cylinder, and clear lines so you can see when all of the bubbles have come out, and that all of the fluid is clean.

The pedal feel on my setup (stock except the S-10 cyclinders) is excellent, I didn't notice any difference, though I will for sure be putting on an adjustable proportioning valve in this winter as it is UNSAFE for a street car to be driven around with those things in...

I only drive my car on nice days, but the rear wheels will for sure lock up before the fronts in a panic situation, or in the rain. I tried it a couple of times on dry pavement to test things out, and the adj valve is a no-brainer to me.

Hope this helps

Billy
Montgomery Village, MD

 

[GrndNatnl]

Thanks for the feedback!

Yeah, the fluid is definitely clean. The powermaster was replaced, as well as calipers and cylinders. So it's had a few full flushes of DOT 3 within the past two years.

I'm just going to bleed them over again, and again, and again, until I get as much air out as possible, and hopefully eliminate that issue.

 

[Turbo6inKY]

Originally posted by GrndNatnl
Thanks for the feedback!

Yeah, the fluid is definitely clean. The powermaster was replaced, as well as calipers and cylinders. So it's had a few full flushes of DOT 3 within the past two years.

I'm just going to bleed them over again, and again, and again, until I get as much air out as possible, and hopefully eliminate that issue.

You sure the parking brake is set right? if the shoes aren't cranked all the way out to the drum, you'll get a really soft pedal until the the shoes hit the drum.

 

[jooset]

MaxVO2

you have a message.

Matt

 

[Rickracer]

If you've bled the system thoroughly, and the self adjusters are free....

...you just need to make the the shoes are adjusted properly. They should just slightly drag against the drums when spun. Next, push your E-brake pedal 3 clicks, and adjust it till the wheels will rotate backwards with a fair amount of torque, but not forwards. Finally, lower the car down, find an empty parking lot or the like, back up and make several hard stops. This will do the final adjustment on your rear shoes, and can be done in leiu of the manual adjustments, and should be done occasionally anyway, to maintain the adjustment.

 

[GrndNatnl]

jooset,

Sorry, been a few days since I checked the board. I didnt get a PM... ?