Pressure Bleeding Brakes? - PeachParts Mercedes-Benz Forum

retmil46 · #1 07-26-2012, 01:00 PM

After the wonderful experience (not) of essentially replacing the entire front braking system, including rotors and bearings, on our 98 F-150, I'm considering rigging up my own pressure brake bleeding setup for future use.

Nothing elaborate - just the main reservoir adapter that I can hook up my own air supply to.

Looking at NAPA Online, you can get the universal adapters in a few different configurations and sizes for anywhere from $45 to $80 ballpark.

My main question is, what pressure is considered sufficient to do a good flush/purge of the system to ensure the system is air-free, without blowing apart the reservoir?

My initial guess would be no more than about 20 psi. Comments?

Air&Road · #2 07-26-2012, 01:03 PM

Ret,

For about $50 or $60 you can get a Master Power Bleeder including the adapter. It is nothing more than a small pressure cannister much like a bug sprayer with a gauge and hose to the adapter. It has a tube that reaches the bottom so that you can put in brake fluid and not have to disconnect and refill periodically.

To answer your question, pressurize the reservoir to about 20PSI.

http://www.eeuroparts.com/Parts/PartDetail.php?partCode=PB&utm_expid=333274-3&utm_referrer=http%3A%2F%2Fwww.google.com%2Faclk%3Fsa%3Dl%26ai%3DC_bezH4MRUNfVMIaFqwHu_YCoApjFz48C4LC KhTHAwcWxRwgFEAEoBVDLpJ2uB2DJztyN_KTMFKAB8Obi6APIAQeqBB1P0Dw_nr_M2N4ITrcTsqFT7J6w7MFj7OkG8bOXLMAFBaA GJg%26sig%3DAOD64_2OTZ90IpOJ16rWlnFJTiwYpBY3sw%26ctype%3D5%26ved%3D0CFYQww8%26adurl%3Dhttp%3A%2F%2Fe europarts.com%2FParts%2FPartDetail.php%253FpartCode%253DPB%26rct%3Dj%26q%3Dmaster%2520power%2520blee der

You specify the adapter you want when you order it. If you work on a different car later, you can buy that adapter at that time.

Hope this helps.

Jorn · #3 07-26-2012, 04:22 PM

like Larry said.

Emmerich · #4 07-27-2012, 12:33 AM

No more than 20psi. The one that looks like a bug sprayer is a pain to use. There is no swivel so screwing it onto the master cylinder requires turning the whole thing around and around to keep the hose from twisting. And when you do unscrew it from the MC, the hose and cap and MC are FULL of brake fluid. Very easy to spill some. And you must clamp the overflow on some master cylinders so it will pressure up.

retmil46 · #5 07-27-2012, 02:32 AM

I checked out the Motive bleeders on Amazon earlier today. As Emmerich pointed out, there were a few complaints that stood out in the customer reviews -

No way to vent pressure from the container, other than unscrewing the entire cap.

The bushing for the pressure gauge was made out of steel, which rusted and contaminated the brake fluid - same gent mentioned he replaced it with a brass fitting.

The "universal" flat adapter, which uses j-hooks and a chain to hold it onto the reservoir, was made out of plastic - anything over 10 psi and it flexed with the pressure and lost it's seal on the reservoir.

I checked out their home website as well. The separate model-specific adapters cost upwards of half as much as a complete basic kit. Given I've got 4 different makes of vehicles to use this on, that's starting to look not so cheap.

NAPA has a flat plate universal adapter, made out of metal, uses the same j-hook and chain fastening system, that will handle up to a 3 1/4" opening, and the fittings are threaded into the plate with standard 1/8" NPT. Price is $42.

My thinking is this - get the very basic kit. Drill and tap the cap or upper side of the container to accept a vent valve. Replace the steel pressure gauge bushing with a brass one. Lose the plastic universal adapter that comes with the kit, and get one of the NAPA metal universal adapters. Replumb the NAPA adapter to add a shutoff and a vent valve at the reservoir.

Stretch · #6 07-27-2012, 03:08 AM

I've got one of these kits - I've had it for years

Gunson | G4062 | Eezibleed Kit

It is quite amazing that it has lasted so long and has been used on so many cars with different master cylinder caps - it is very much DIY quality - not professional quality - but it is soldiering on today.

Here's more information about it

http://www.gunson.co.uk/items/pdf/Products/G4062_booklet.pdf

that you might be able to use to your advantage.

The biggest problem with the system is that you are meant to use pressure from a spare tyre as the pressure source. In principle this is all good though at 20PSI you need a nice big tyre to keep yourself going whilst bleeding a W123.

I've now hooked it up to my air compressor via a pressure regulator of course!

alabbasi · #7 07-27-2012, 04:07 AM

Get a motive pressure bleeder.

Air&Road · #8 07-27-2012, 08:33 AM

Yes, the Motive has it's drawbacks, but it is an economy unit. To get anything better in today's market costs big bucks.

BTW, you don't have to turn the whole unit. You simply twist the hose a few turns backwards before threading on the cap.

If I ever put out a shingle and start doing a lot of work I will buy a pro unit. For my occasional brake work, the Motive gets the job done quite well. If I had neighbors any closer than a half mile, I wouldn't even bother with the Motive. My wife never seems to be around when I need to bleed or flush brakes, so it serves the occasional purpose quite well.

Dudesky · #9 07-27-2012, 09:38 AM

I got one of these, does the job.

I made one where you have fluid in the bottle and the tube is below the fluid level so no air goes back...it was ok, Motive is better.

MS Fowler · #10 07-27-2012, 10:17 AM

I am the king of cheap solutions---at least in my own mind. For years I used a dedicated ( only, ever put brake fluid in it) pump type oil can. A piece of vinyl tubing slipped over the end of the spout and slipped onto the bleeder. A few pumps and it was done.
More recently I have used a Mity Vac in both vacuum and pressure modes.

rs899 · #11 07-27-2012, 10:37 AM

I just made my own out of a cast-off gallon plastic garden sprayer. For an MB, found an old cap, drilled a hole through it. Removed the wand assembly and used the ferrule that secured it as a nut to fasten the cap to the control handle. It's a bit more difficult to use than the purpose built ones, but the price was right.

You don't need the gauge, really. Just start with a dozen strokes and see what kind of flow you get- increase as needed ( within reason)

However you make or buy it, you will kick yourself for waiting so long to use one.

Army- we don't have Gunson's here. Good solution- 26 pounds? ouch...

retmil46 · #12 07-27-2012, 12:47 PM

Quote:

Originally Posted by rs899

I just made my own out of a cast-off gallon plastic garden sprayer. For an MB, found an old cap, drilled a hole through it. Removed the wand assembly and used the ferrule that secured it as a nut to fasten the cap to the control handle. It's a bit more difficult to use than the purpose built ones, but the price was right.

I'm starting to think the same way. In reality, that's all the Motive unit is anyway - a glorified garden sprayer with a pressure gauge.

I've got two or three unused sprayers sitting in the barn. Heck, for that matter, a brand new one isn't that much from Wally World. And I can get a simple 15 psi pressure gauge from Advance for about $10.

Youtube has plenty of videos from other people doing the same. Even that gent from WA state, who's MB site shall not be mentioned here, has a how-to video on it.

Stretch · #13 07-27-2012, 01:01 PM

Quote:

Originally Posted by rs899

...
Army- we don't have Gunson's here. Good solution- 26 pounds? ouch...

I didn't think they'd make it over the pond (especially at 26 quid a throw) but when I bought mine 20 years ago the price felt more like 8 pounds 95 I must say...

...I think they're trying to corner the yuppie car mechanic corner or something...

rs899 · #14 07-27-2012, 03:38 PM

I have their carb sync tool and Colortune for my Britcars.

Colortune is interesting- a glass sparkplug for helping you set the proper mixture

Stretch · #15 07-27-2012, 04:02 PM

Quote:

Originally Posted by rs899

...
Colortune is interesting- a glass sparkplug for helping you set the proper mixture

Have you ever ever ever managed to get it to work for you?

I haven't had a petrol car for nearly 6 years now but I gave up trying to see in that sodding window about 22 years ago!