All was well with the first 3 corners of my brake flush this Sunday, but I snapped the bleed screw off on the driver's side front, with maybe 2 sets of threads showing.

Wondering if anyone knows:

1) Was there only the one supplier for the front brake in 1989? I know until 1988 it was Girling and Teves (from the Haynes), but the selection on rebuilts is downright confusing.

2) Can anyone confirm the bleed screw is M8x1.25? If possible, I'd like to just replace it.

3) Anyone have experience drilling out the bleed screw?

4) To prevent air getting up to the ABS Unit, can I clamp the brake line?

Thanks!
Bruce 190D 1989 60K miles

I have backed out broken bleed screws with an ez out style tool.
Because they are already hollow I was saved from drilling.

I cannot confirm size or thread pitch.

__________________
80 300D 340K Owned 30 yrs
83 300SD 440K Owned 9 yrs - Daily Driver 150mi/day
02 Z71 Suburban 117,000
15 Toyota Prius 2600 miles
00 Harley Sportster 24k
09 Yamaha R6
03 Ninja 250

As has been mentioned an "Easy Out" solution is much less problematic.

The manufacturer's name will be on the caliper.

EPC shows bleed screw as: part number 000 420 46 55
(The 000 means it's an Industry Standard part and NOT a Mercedes specific part.)

VERIFY the correct part number WITH your V.I.N. from the Parts Specialist !

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'84 300SD sold
124.128

If you have to drill PepBoys sells left hand Drill Bits. I beleive they were packed one pere pack.

They also have some cheap Metrick tap and drill sets.

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84 300D, 82 Volvo 244Gl Diesel

I too have used the left-thread EZ-out style on a caliper bleeder screw. However, be forewarned: it does take a rather good "feel" for the force you're imparting; if that breaks off, you're going to have a dickens of a time getting it out or drilling it because it's hardened.

If you have to drill, remove the caliper and disassemble first. The last thing you want is some minute particle damaging the caliper.

You'll likely seriously damage the brake line by clamping it. They are not meant for that. Obviously a pressure bleed will be required when you're finished.

Good luck.

Some heat can help. I would not do as I suggest unless you have done it many times on fasteners.

Thead a nut on the remaining threads and mig weld it to the remaining shaft. The heat from the welding seems to break up the rust.

It is even trickier on a hollow bleed screw as well. Takes experience and judgement. A little intense heating does not require as much skill but you have to have a torch set and the easyout.

also, i suggest you soak the part with something like Kroil. Soak it overnight.

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Ben
1987 190d 2.5Turbo

I always use the MIG welder to get them out put a 8mm (3/8) over the nipple and weld them together. If the weld is good you can use a ratchet to get it out.

__________________
600SEL '91
300E 4Matic '88
240D '83
280SE '77
350SE '73
The most complex systems can fail in the simplest way.
Contra verbosus noli contendere verbis, sermo datur cunctis, animi sapientia paucis.

i don't believe in the lord! He's never bought me a Mercedes Benz.

Use these extractors made by Ridgid, _ALL_ others are folly.

No. 10 Screw Extractor Set - RIDGID Professional Tools

Drill a hole, hammer in the splined shaft, drop the drive nut over the spline. You now have bidirectional drive of the bolt. This is critical because when the bolt is stuck with rust, gently working it back and forth is worlds better than just giving it a twist. Giving it a twist is what broke it in the first place and anything you hammer into the center is going to be weaker.

If at all possible use a socket and " T " handle driver with both hands, this cancels out side loads that make the bolt harder to remove when turning from a single point. ( For stuck bolts that still have a head, using a T helps as well.)

Tapered so called easy outs only grab a small surface area near the top and tend to flare the bolt out further locking it in the hole. As I said, all others are folly.

Did your bleeder snap due to rust or prior over torque? Drilling through the bleeder even with a bit the same size as the existing hole helps. Look at a intact bleeder screw, the tapered end is what does the sealing. If you drill out the end the metal now can relax taking the taper friction out the equation. Tapping the end of the bleeder helps to crush the taper as well. Drilling larger than the existing hole can damage the bleeder seat, check max size on another caliper.

If it is rusted in, external heat can help, just be sure to drain fluid as it will burn. Anti sieze on the threads prior to install helps.

When bleeding is complete, spray the open bleeder hole with brake cleaner / carb cleaner, blow out with air, then install a rubber cap / vacuum cap / hole plug that comes with a new caliper. Brake fluid absorbs moisture and will cause rust as will water laying in the bleeder hole.

The heat from the weld is what really loosens them up in my opinion. Breaks the rust connection between the metals. Or at least makes them far easier to remove. We live in a rust belt and many would not believe how bad some bleeders are.

A standard practice here is to heat the immediate area a lot. Throw a water saturated wet rag on it. Or use a spray bottle. Do this three times and even a terrible looking bleeder will release pretty easy. Any attempt to directly loosen them outher wise will usually break them off.

After I have bled down usually I cut short lengths of fuel hose neoprene tubing. Put grease on the bleeder screw. Slide the short tight fitting tube over the fitting and top it with more grease forcing it into the hose.. Seems to work pretty well for me and sure makes it easier for the next guy or time they require loosening.