Not an issue after like 4 years for me, and probably 12-15 bleeds and flushes. I know of many other people that use them regularly on track cars with no problems.

But, I guess anyone can make any generalized statement they wish.

 

^^^More substantiated personal experience with Speed Bleeders. They really are a great product.

 

I have them on my wish list at PP - $13/set is worth giving them a shot IMO -

 

Ed, what brake set-up do you have and are you completely satisfied? Or do you need to go bigger? I assume you track your car.

Alfonso

 

I've got 993 calipers over 309x32mm rotors up front and stock rotors in the rear with a 23mm m/c. It is plenty of braking for me and I get ludicrously long life out of pads now and no real degradation due to heat after a day or two at the track. I'll probably go to 930 rotors at the rear with the next pad change.

 

You could still 2-man the speed bleeders, couldn't you? By having a helper stand on the pedal, and then open the bleeder screw, you could raise the bleed pressure. That way, if there is air trapped in the brake proportioning valve, you could bleed that air as well. After breaking the lines, I usually tap (read pound) the calipers with a rubber or plastic mallet to force the air bubbles loose. You ideally want a lot of fluid flow to force the air bubbles to move out of the lines.

 

Speed Bleeders could be a two man operation, you'd gain the one way valve effect that would mean you could be out of sync when tightening back up and not sucking air.

 

Speed bleeders are not necessary, unless for some unknown reason you like them. Provided you fill the waste bottle with fluid enough to submerge the end of the clear plastic tubing, releasing the brake pedal cannot draw back anything but fluid. Simple as that.

The original question of this thread was whether or not new cylinder seals could cause a spongy brake pedal. New cylinder seals are not nearly as likely a cause as is trapped air, which is difficult to remove from four rebuilt calipers. Normally a thorough pressure flush can be a benefit in that regard.

 

I agree with you on the air in the system thing, and that needs to be addressed in whatever way. But, "for some unknown reason", the SB's are a great solution and the easiest/best way to bleed, in my opinion. This is for future reference when people search "Speed Bleeders" here. It does not sound like you've used them and continue to dismiss them as a joke, when the reality is otherwise.

 

wait, what you just wrote is that the "one way valve" can suck air from some sort of a waste fluid side (be it in the hose to your catch bottle or in the bottle) BACK INTO the system.

that is contradictory of a "one way valve" isnt it?

 

The caliper seals have a square cross-section profile, which is what causes them to retract the pistons.

I doubt that they would retract the pistons enough to cause a lot of pedal travel.

I also agree that the cuprit is probably excess air in the calipers. The goal is to move fluid, and the best way I've found is to two-man the operation, with a helper pushing on the pedal firmly, so that the release of the bleed screw cause the brake fluit to shoot out, taking air with it.

 

I recommend a thorough pounding of the calipers while pressure bleeding. You want to literally rattle the caliper to shake loose any air bubbles adhering to the walls of the formerly empty cylinder. I had a similar experience when first filling my completely fresh brake system (brand new front calipers, rebuilt rears). I pounded them good with a rubber mallet as the fluid flowed and watched the air bubbles flow out on the second round of bleeding.

Anyone reading this who hasn't redone your brakes... when you fill your empty brake calipers for the first time, be very careful with your first drive, or you might have a major pucker moment. Hopefully your driveway is sloped downward so you'll know by the end of the driveway whether you can stop or not. If you don't find out until the first stop sign, it may be too late.

Brett

 

I have seen air sucked in around the bleeder threads, or into the line when bleeding. Like on a pressure bleed, there is a constant source of bubbles in the catch-bottle hose - sometimes they come from around the bleeder threads in the caliper. If the problem continues, it may be a good time to look at the master cylinder. They always seem to tank right when your doing brake maintenance. Also don't neglect the cluch while you've got the mess already made.

 

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Prior to rebuild, my front wheels didn't spin free with normal pad drag on rotors. But after rebuild, there was about 1 mm clearance. That measure of clearance is not enough to cause excessive pedal travel, but rather the pad/rotor drag is a sign of cylinder seal wear. I don't know. Thanks for getting back on topic.

 

Discussing bleeding certainly seems "on topic" here.