merchauser

Flushed old brake fluid today using the Motive Power bleeder. Went well except for RF outside bleeder
which only had minimal seepage out of the base of the bleeder. Helper pushing on pedal could not get
any fluid to come through.
thinking caliper needs rebuilding?

Geo55

Did you check to see if the bleeder was plugged?

Mrmerlin

get a piece of mechanics wire remove the bleeder nipple, gently probe for the port in the nipple, once the wire goes through you should be able to bleed as necessary.
Without knowing how the car has been used,
and what kind servicing and environment its been in.

Suggesting a caliper rebuild is needed might not be needed to restore braking efficiency.
BUT putting new calipers seals and boots is always better than the original parts

StratfordShark

+1 on new seals and boots.

Installing new seals and dust boots resulted in fantastic feel and control for my brakes. At same time I replaced all flex hoses and installed new support plates after cleaning up corrosion, but I could tell from how easily and smoothly the pistons moved with the new rubber - testing with puffs of compressed air - that it made a huge improvement on the old parts (note the pistons were all in virtually new condition - I smeared them with brake grease but didn’t need to clean off any crud, so the new seals and boots were making a big difference)

dr bob

928 International (and others too I'm sure) sell a kit of new bleeder screws. These are fresh, pretty new pieces glowing with that sweet golden hue that only fresh cad-plated bits bring to the project. IMO these are necessary pieces for any caliper refinishing project. Also handy for replacing those rusty old pieces you have now, the ones plugged up with guck that's been slowly gathering in the bleeders. The kit comes with new dust- [read: crud-] caps too so there's less chance of it happening again. IIRC The kits were not at all unreasonable.

merchauser

took at the culprit bleeder and there does not appear to be a hole near the tapered tip??
looks like a defective bleeder?

Mrmerlin

its there, its just filled with crud get a piece of mechanics wire and probe,
better yet wire brush the tip to reveal the port

dr bob

^^^ This ^^^

It's OK to use a small drill bit by hand to help extract the hardened brake dust and rust that fill the bleeder screw. The bleeder hole is a straight shot from the outer end, then Y's to two openings in the tapered tip at the other end. Don't Damage The Tapered Tip of the Bleed Screw At All. That and the almost-matching taper in the caliper are what makes the seal when the bleeder is snugged down. Note also that it really does just need to be snug to seal. "Tight" increases the risk of it seizing in the aluminum caliper. Add a little anti-seize or silicone grease to the threads (only) when you reinstall, to keep hygroscopic brake fluid and subsequent moisture from corroding the caliper and seizing the bleeder. Be sure that you have the caps installed on the bleeders too when you are done, so no new crud gets inside.

-----

My essential prep chems for this stuff:

-- Silicone "plumber's grease" is waterproof, very handy for sealing bleeder screw threads as you bleed. It stays in the threads pretty well even under higher temps, as the bleeders are outer-end-up.

-- TFE thread sealing paste is similarly handy for bleeder screw threads. No serious worries about the effects of heat.

Both of these products show up in the plumbing aisles at your favorite Home Depot or other hardware store.

Petza914

I have a little parts drawer full of pristine Porsche bleed screws as I replace all of mine with stainless speed bleeders. Let me know if you want a couple for the cost of the postage and I can drop them in the mail on Monday.

merchauser

[QUOTE][/I have a little parts drawer full of pristine Porsche bleed screws as I replace all of mine with stainless speed bleeders. Let me know if you want a couple for the cost of the postage and I can drop them in the mail on Monday. QUOTE]

thanks. just sent PM

merchauser

FWIW: not sure if others have had this issue, but after all the helpful posts regarding this problem,
it turns out this particular bleeder did not have any holes at the base! it was very clean when I took it
out, but I soaked it in carb cleaner overnight, and without question, there are no holes at the base of
the bleeder: so the bleeder is defective.
thought I would post this in case anyone else has had this problem?????

hlee96

I’m confused though. If the bleeder did not have a hole for bleeding, how would one go about bleeding the brakes for proper function without any telltale signs of bubbles in the system? Unless the last brake fluid service person just let brake fluid drain out of the base of the bleeder in order to get all the air out of the caliper. ??

merchauser

to be clear, it has the upper hole covered by the rubber boot, but no holes are the base!?? go figure.
my car came with a good deal of receipts, with lots of work done, but no receipts for any brake work,
so no idea if this bleeder is a factory defect, or someone replaced it at one time.
there was no way to bleed the out RF caliper!
anyone else ever have this issue??

Geo55

That just seems funky. Never heard of it before ...on any caliper. I wouldn't think that a Porsche assembly person would let that got through, yet alone during the bleeding process at the factory. Hold on to it though good conversation piece.

Petza914

Nope, never came across this before. Can you post up some photos of the top and bottom of the bleed screw? I want to see your unicorn bleed screw?