Hey guys, I was planning on bleeding/changing the brake fluid on my 88 M3. I'm not to sure about the order I should go about bleeding them and if I should pour in the fluid while there is still a little old brake fluid in there or wait until it is completely flushed out. Also if I have to do anything special for ABS. I am bleeding them manually (no vac pump, someones going to be pumping the brakes here). Any and all help is greatly appreciated!
start by getting the old fluid out of the reservoir. I use a vacuum bleeder tool, but people have mentioned a turkey baster (if you grab the one in the kitchen drawer, you might want to plan on replacing it with a new one by Thanksgiving...... toxic brake fluid and brake parts cleaner aren't exactly the most desireable additions to your basting sauce.... but, I digress..) Start by bleeding the corner furthest away from the master cylinder and fluid reservoir. Not sure on an E30 M3, but on a non-M3 E30, the fluid reservoir is on the driver's side of the engine bay, so I start with the right rear, then the left rear, right front, and lastly, the left front. Don't let the reservoir run dry or get air into the master cylinder. After draining the reservoir, I fill it with fresh brake fluid, bleed a caliper a bit, and top up the reservoir as needed, throughout the bleeding process. If you want to do a more thorough bleeding (and you have a manual transmission), bleed the clutch slave as well. After bleeding the clutch slave, you'll probably need to remove it (to let the piston extend), and re-install it, otherwise your clutch pedal will get stuck to the floor. Bleeding manually by pushing down the brake pedal, after you open the bleeder, you'll want to close it before whoever's pushing the pedal bottoms the pedal out at the full extent of it's travel. The process is - pump up and keep pressure (pushing) on the pedal; crack the bleed screw to bleed, & close the bleed screw before the brake pedal bottoms out. Whoever's pushing the brake pedal should give you a shout when to close the bleeder, and needs to know/feel the approximate full length of pedal travel to tell you when to close the bleeder. You don't want to open the bleed, and pump the brake pedal down, then let it up, and back down again - you could suck air back in at the caliper end of things. It takes a special BMW tool to cycle the ABS unit; since there's not much you can do about that, I wouldn't worry about it too much. Working the ABS will cycle fluid through the ABS; not a problem for a car that's tracked and has the fluid changed relatively often, but if you have a garage queen that only goes out on sunny days, you'd have to do some hard stopping to engage the ABS, vs the many cyclings you can get with a little heavy braking (and no traffic in front/behind you) on rainy days. If you use ATE Super-Blue, they also have a gold-colored brake fluid (same specs), so if you alternate them from one flushing to the next, you know when you've got a line completely bled out. That's what I can think of for the moment, I imagine others should have some tips as well
+1 to all above I don't like the manual method for one simple reason- you rarely ever put the pedal to the floor. If you do it a bunch of time while bleeding the brakes, you can finish off the master cylinder. I have seen it happen. Same goes for the clutch, but to a lesser extent because you do regularly floor it.
I gotta agree with Paul here. I am pretty Old Skool, so I tend to bleed brakes by gravity feed if I have the time. No pressure; no suction. Takes awhile longer, but unless you're in a low-gravity location (like the moon), it will work.
Hello: Bavarian Autosport and BMP Design sell pressure bleeders for around $50.00. It pays for itself after one use. Just don't over pressure the system, 10 to 15 psi is enough. You can do the job yourself without a helper and is a little quicker than gravity feed. You should do this once a year. It is amazing how dirty your brake fluid gets after one year. My 84 has all new hoses and master and slave cyinders and it is still amazes me how dirty the fluid it. You also get that nice hard pedal afterwards. GR
Yeah the guy I bought it from didnt seem to like the car as much as I do, you have no idea how dirty that fluid is. Thanks for all your suggestions!
