S10 wheel cylinders put in, only holding 2lbs!?

[Crazy D]

Ehh...wtf. My rear tires start to spin at 2psi of boost. I think they held more last season at the track. Now granted these are with 275 BFG TA's, but is it gonna magically improve to 8 or so with ET's? Am I missing something?

 

[Jimn8or]

Are your shoes cut to match your drums? How's your shoe adjustment? Did you get the new whl cyl 'keepers' on, or use the old ones...lots of variables here dude. Adjust the shoes to fit tight and 'wear in' to your drums. They'll work better than 2lbs for sure.
Jim

 

[Crazy D]

Here's something that might be relevant.... my car has the vacuum brake conversion. It's thought among a few that since I'm building boost, I don't have enough vacuum to hold the brakes. I think not so many would have done this conversion if it screwed them so. Help?

 

[Dan Thompson]

Something is wrong. I have the S-10 also and I can hold maybe 4# on a good day.

The easy way to get the cylinder locks in place is with a big socket. I think its 1" or maybe 1 1/8". Hold the cylinder in tight with a piece of wood and tap the clip on with the socket and hammer.

 

[Bryan 94 Z28]

The wheel cylinders have been installed correctly, with the new lock rings.....they have both been bled thoroughly. The shoes are NOT new, but they have plenty of padding left. The drums are perfectly smooth, no cuts or grooves, and no cuts on the shoes either. Master cylinder has plenty of fluid in it as well.

The self adjustors have had plenty of driving time to allow them to adjust the shoes to their tightest positions.

I get the feeling it's because of the vacuum brake conversion we did on it that we aren't getting any braking power once we pass pressure equilibrium. The instant the boost gauge shows any amount of boost, the car will try to start rolling forward, no matter how hard the pedal is pushed.

Maybe the e-brake can be used to accomplish the same task (yes, I know the e-brake doesn't use the hydraulic system, it uses the cables, but what the hell).

 

[Crazy D]

bump

 

[wagon]

You say that the adjusters had time to adjust the shoes to thier tightest psoition. Well, I don't ever rely on these. They only adjust when you apply the brakes while going backwards, and I never trust them. I always find them sticking, even if I buy new ones, and lube the heck out of them when I put them in. What I do to get them to hold tight is tighten the adjusters myself, until the drum still moves, but with a bit of resistance. Not a little, but not a lot, either. I like to think that I am letting them 'self clearance'. This seems to work best for me. I have been able to hold 25# of boost this way. Of course, I have the Powermaster, so I have no experience with vacuum. Good Luck.

Brian

 

[Steve Wood]

Vacuum brakes should have nothing to do with it as long as the parts are all functioning and the system is properly bled.

 

[GNSCOTT]

I was able to hold 10psi + with the cylinders. I used the stock clips, soft compound shoes etc. I was able to hold 4psi stock.

 

[SPOT MY 6]

Originally posted by Jimn8or
Are your shoes cut to match your drums?

Jimn8or, what do you mean by this? When I have my drums cut should I bring them the shoes too? I didnt know you can cut the shoes???

 

[TurboDave]

Originally posted by Bryan 94 Z28
The wheel cylinders have been installed correctly, with the new lock rings.....they have both been bled thoroughly. The shoes are NOT new, but they have plenty of padding left. The drums are perfectly smooth, no cuts or grooves, and no cuts on the shoes either. Master cylinder has plenty of fluid in it as well.

The self adjustors have had plenty of driving time to allow them to adjust the shoes to their tightest positions.

I get the feeling it's because of the vacuum brake conversion we did on it that we aren't getting any braking power once we pass pressure equilibrium. The instant the boost gauge shows any amount of boost, the car will try to start rolling forward, no matter how hard the pedal is pushed.

Maybe the e-brake can be used to accomplish the same task (yes, I know the e-brake doesn't use the hydraulic system, it uses the cables, but what the hell).

Don't rely on the self adjusters, they rarely work as designed.

Couple of things to try.
Adjust them out so that you can just get the drums over them.

Get the drums turned. Perfectly smooth drums aren't helping.

Unless you have a linel lock, you are defeating everything by doing a burn out, or by trying to hold boost on anything but a cold drum/shoes!!!!!! I drove to a local shopping mall parking lot one day to try some foot brake "holds". The brakes got warm enough just driving there to render them almost useless (car started moving at only 8#)

Let them cool down, and I could hold over 15#.

One other point, when you buy a new set of brake shoes, get ONLY organic, and buy enough sets for two cars. Then install the long shoes in all four places.

If the drum integrity is good, the shoes are adjusted properly, and things are cooled down, you should have problems.
I say "should", because I'm not all that convinced that vacuum brakes have the holding power of the Power Master system, and I've not converted over for that reason, but I can't say for sure. there have been those that claim they can hold boost with the vacuum system (15-20#??? Hmmm I wonder).

Good luck.

 

[don86T]

As Dave said, I was suprised how well the brakes held after using line locks. I'm still using a power master also.

Don

 

[DonnieShort]

I use the S-10's also and 2 sets of brake shoes using the longest ones and I have a vaccum conversion system. 15 psi is no problem. Switching to vaccum is the best thing I've done. I too was worried the vaccum brakes would hold, but it holds just as good if not better than the powermaster not to mention the peace of mind it gives you. Plenty of stopping power after a run too.

 

[tom h]

TurboDave,

from your description it appears you are running S10 cyls, and also 4 each of long, softer (organic?) brake pads.

Have you had problems with, or concerns about, rear wheel lockup for street driving?

For sake of discussion, let's assume a reasonably sticky street tire, like BFG or Nitto drag radials, in larger size (eg, 255-275 mm section width).

 

[TurboDave]

Originally posted by tom h
TurboDave,

from your description it appears you are running S10 cyls, and also 4 each of long, softer (organic?) brake pads.

Have you had problems with, or concerns about, rear wheel lockup for street driving?

For sake of discussion, let's assume a reasonably sticky street tire, like BFG or Nitto drag radials, in larger size (eg, 255-275 mm section width).

Nope, I've never had a problem with the rears locking too early (this car is a daily driver).