Missing Bleed Screw?

[salguod]

So, after being on hold due to business of life and cold temps, the never ending brake job on the 318ti is in its home stretch. I've patched the blown metal line (flaring brake line above your head while on your back on cold concrete in 40-something degree F temps is not for wimps), time will tell if it will leak or not. I dug into repairing the parking brake and after surveying all the rusty bolts, I decided to live without it. So, all that's left is replacing a front brake hose and bleeding the system. Before digging into the hose replacement, I decided to give each bleeder a good soaking in PB blaster. When I get to the LR, I'm confronted with the attached image.

Note the absence of a bleeder screw? There seem to be no threads, there is no broken bleeder in the hole (EDIT: Looking at it again compared with images of broken bleeders, it does look like what I've got is a broken bleeder.) and no evidence of leaking fluid. It feels like a blind hole, maybe 10mm deep. All the paperwork I have on the car, including receipts back to new, show no caliper replacements, so this is likely the BMW original part. There is a receipt for a brake flush by the dealer in 2000. How'd they do it with no bleeder?

It doesn't make sense and I hate the idea that I probably have to buy a caliper just to bleed the brakes. Argh.

Anyone run into this before? Any ideas aside from replacing the caliper?

[zoner]

My guess is that they either didn't bleed that corner, due to the bleeder being already damaged, or they caused the damage when tightening down the bleeder screw after bleeding. It would make sense that it's not leaking- the portion that does the sealing is at the unexposed end of the screw, not the exposed end.

I imagine you could very carefully try using an extremely small screw extractor to see if that will loosen it enough to be able to be backed out- you wouldn't have to drill it, since there would already be a hole in the bleeder screw, but I'm not even sure they make screw extractors that small. Another idea would be to drill out what's left of the screw and re-tap the bleeder hole to accept a larger bleeder screw, but by then you're starting to put time and effort into it, with no guarantee of success, that would probably exceed the cost of just buying a rebuilt caliper- as cheap as $30-40 online.

Good luck with whatever you end up doing!

[BlackBMWs]

^^+1

[salguod]

I've already got the caliper on order from Bavauto. Trying an extractor or drilling it out just sounded like too much trouble. I hate waiting a few more days for the part. I just hope that I don't break another bleeder once I finally get everything together.

[1996 328ti]

I would be afraid of drilling. Isn't brake fluid flammable?

[BlackBMWs]

Only if mixed with gasoline.


JK, good question!


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[salguod]

I was more concerned with getting metal shavings in the cylinder, although bleeding should flush them. The bigger thing was it seemed like more than $60 of pain to try to extract it with a decent chance of failure.

[1996 328ti]

When I had my hard lines replaced I must have flushed them 4 times. Maybe more.
Only system that worked was the 2 person method by pressing the brake pedal in. Vacuum didn't work well.

[BlackBMWs]

Same with a pressure bleeder, although I use it to flush the system, I get Wifie involved for the final bleed to get it done well. She has developed a strong right leg.


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[salguod]

I'm planning on the old school 2 person bleed. I'll also need to activate the abs because it seems likely that I have air in there when the line under the driver's seat failed.

My plan is to try to gravity bleed first (open the bleed screw and let it run), followed by cycling the abs and then the 2 person bleed. Gravity bleeding has worked well on other cars, but I haven't tried it on one with abs yet.

[salguod]

Well, finally got it together. Vacuum bleed worked very well on the fronts, but the rears didn't want to cooperate. They wouldn't gravity bleed or vacuum bleed. I even tried shorting the relay to use the ABS pump to bleed them with no luck. Finally tried the old 2 person method which worked well and revealed a nice, even stream of fluid with no air spurts at each wheel.

Pedal feels pretty good, but maybe a bit spongy. I think it's just my paranoia, though. ABS kicks on fine too.

[1996 328ti]

Originally Posted by salguod

Pedal feels pretty good, but maybe a bit spongy. I think it's just my paranoia, though. ABS kicks on fine too.

I felt the same thing. I always 2nd guess myself after bleeding brakes.