Ron

I made this using a Nalgene bottle, a brass nipple, and a length of copper tubing. With a little fluid in the bottom all I have to do is hook it up, open a bleeder valve and pump away without any air entering the system. I soldered the cooper pipe to the nipple and the setup is rigid so you don't have to worry about the tube moving around and getting air in the system.

I do have a Motive bleeder but this setup seems easier with less stuff to mess with.

nile13

Interesting. How exactly does it attach to the bleeder valve? Do you have a pic of the top of the nipple?

Ron

You put a piece of tubing from the top of the nipple on the nalgene bottle to the brake nipple. You do have to drill a hole or two from the inside of the cap to vent it otherwise pressure would build up inside the bottle. I drilled four very small holes in a postion so that if the bottle did fall down the fluid in the bottle would not splash out. The piece of line on the top is that coated fishing line that is crimped in a loop at the top so I can hang the bootle if I want.

nile13

Aha, so you do use flexible line between the nipple and teh bottle. That's what threw me off, a mention that there's nothing flexible in teh system.
Thanks!

Edward

Ron,

One of the advantages of using a pressure-style bleeder (like the Motive) is that you don't have to depress the brake pedal while bleeding which can push the piston in the master cylinder beyond its normal wear point. I recall others (R.Calvo comes immediately to mind) have ruined, and subsequently have had to replace, the mc after such bleeding practices. Just an FYI for you, if you're interested

Edward

STLPCA

Apart from Edward's important point, if you allow the pedal to lift while the bleed nipple is loosened, air can be sucked in since the threads may not be air tight. Plus, won't you be sucking the discarded fluid (if not air) back into the system? It is, however, quite an impressive catch bottle.

Ray Calvo

Like Edward said, if you bleed via pumping the pedal, you will prematurely destroy the brake master cylinder. Went thru TWO within a year bleeding this way on old '76 911.

Porsche has the same warning in the shop manual about pumping the brake pedal - read yours!

Flying Finn

Ditto to what Edward & Ray said.

Ray,

just to save you from extra typing in the future, have you seen this nice little "smiley" that John D. has created ->

nile13

While we are on the subject - does nything special need to be done to bleed ABS? Or is it not really needed for a standard bleeding job?

Martin S.

My pal Cup Car says that there is a down side to the pressure bleeder (I have one and do like it). He reminds me that the whole idea of bleeding the brakes is to get the air out. Who can argue with that. He then mentioned, why would you then want to inject fresh brake fluid under (air) pressure, sometime over 1 bar? Hmmmm I said. The proviso is when pumping the brakes, you don't take the brake pedal past its usual range of motion. Why is everything so complicated?

Edward

Hey Martin !

The only function of the pressurized air is to push the fluid out. Assuming you don't let the brake fluid resevoir go empty, there really is no possibility of injecting air into the system. Think about it: in the resevoir, mildly pressurized air is introduced through the cap and above the heavier brake fluid; the fluid then drains out of the bottom of the resevoir. Really not much to it

Edward

Martin S.

I feel better already...especially since I already paid for my pressure bleeder.

Pete Lech

Nope, it works like the old-timey systems.

I use a Mity-Vac. Maybe not as good as a pressure bleeder, but easier to carry with me on those occasional track days. Better than Mom's turkey baster to empty the resevoir when doing a brake fluid flush too. I use it on the whole fleet.

Ron

I've been bleeding brakes on Mercedes vehicles for over 20 years with a catch bottle but without the tube that goes to the bottom of the bottle in my current setup with no problems. Maybe Mercedes master cylinders are different than Porsche; I would think all master cylinders are designed pretty much the same but then again I really don't know.

I made the current catch bottle to use on my Mercedes vehicles. About 2 weeks ago I bleed the brakes on my 300E and had to have my wife pump the pedal while I opened and closed the bleeder valve at the appropriate times. She didn't like helping me so I decided to make my current creation. I used this catch bottle on my ML 320 just the other day and it was great because all I had to do was open a bleeder valve and pump the pedal. For whatever reason even though the bleeder valve is left open the old fluid in the catch bottle is not sucked back in to the system.

I had planned on using this bottle on the Porsche too, but maybe I should just stick with my Motive pressure bleeder for the Porsche.

I'm going to ask Cory at Autometrics about bleeding the brake by pumping them. I'm pretty sure that's how it's done at the track. In fact I did the pumping of the brake pedal on a GT-2 at Carolina Motorsports Park last year while the fluid was being changed.

Ron

Cory at Autometrics said you will not damage the master cylinder if you bleed the brakes by pumping the brake pedal unless the seals in the master cylinder are very old and worn out.

I also read my workshop manual and the proper way to bleed the brakes after fitting a new master cylinder is to pump the pedal. It does say to use only a half the brake master cylinder stroke in certain cases. See page I included below for specifics. The manual does talk about bleeding the brakes with pressure in other parts. I did not see any warning or statement that said bleeding the brakes by pumping the pedal will ruin your master cylinder or that you should not do same.

Remember I'm just reporting what I've read and what I've been told; so don't kill the messenger if you don't like his message.

Workshop manual page