Pressure Bleeding Brakes? - Page 2 - PeachParts Mercedes-Benz Forum

MS Fowler · #16 07-27-2012, 05:21 PM

Quote:

Originally Posted by Army

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!

I really liked the concept, back in the day. What bothered me was that you can only see ( if you can see anything) the color at idle, or at high speed, no load. You cannot see the color under hard acceleration---unless you have someone tie you to the fender.

Stretch · #17 07-28-2012, 03:33 AM

Quote:

Originally Posted by MS Fowler

I really liked the concept, back in the day. What bothered me was that you can only see ( if you can see anything) the color at idle, or at high speed, no load. You cannot see the color under hard acceleration---unless you have someone tie you to the fender.

Indeed!

It is incredibly difficult to see inside that little window anyway and the glass is only thick enough for low pressures - so even if you could entice the wife onto the front of the car whilst you drive at various break-neck speeds and simulate tricky engine load situations the chances are that the window wouldn't hold...

retmil46 · #18 07-28-2012, 01:47 PM

I tried the Colortunes myself a few years back, as well as the exhaust gas analyzer, on my old 87 Subaru wagon.

Same result here - couldn't see crap.

Stopped by Wally World last night. Picked up a FloMaster garden sprayer for $8. They had ones supposedly rated for bleach, degreasers, and stronger chemicals for $14.

I can get a Mr Gasket 0 - 15 psi pressure gauge for $10 at Advance - that's what I use to read fuel pressure downstream of the filters on the Liberty diesel.

Kicker is, other than for the 87 300D, seems that no one, not even the dealer websites, sells just the cap for the fluid reservoir for any of our other 3 vehicles. Guess I'd be just as well off to buy one of the universal adapters from NAPA, instead of having to keep track of 4 different adapters.

tbomachines · #19 07-28-2012, 01:52 PM

Here's an idea that I had - take a 2l soda bottle, epoxy in a schroeder valve from a bike tube into the side of it. Drill a hole in the cap and stick a tube into it (sealing it). Grab a spare mc cap or adapter and seal the other end of the tube to it. Put fluid in the soda bottle and pump it to 15psi with a bike pump or compressed air or something and youve got a power bleeder for almost nothing! I haven't built it yet but I'd have to imagine it would work great...sorry if it's a bit hard to follow I'm typing from my phone.

Stretch · #20 07-29-2012, 03:40 AM

Quote:

Originally Posted by tbomachines

Here's an idea that I had - take a 2l soda bottle, epoxy in a schroeder valve from a bike tube into the side of it. Drill a hole in the cap and stick a tube into it (sealing it). Grab a spare mc cap or adapter and seal the other end of the tube to it. Put fluid in the soda bottle and pump it to 15psi with a bike pump or compressed air or something and youve got a power bleeder for almost nothing! I haven't built it yet but I'd have to imagine it would work great...sorry if it's a bit hard to follow I'm typing from my phone.

In principle that sounds good (I think) but you'd have to have a pretty strong bottle to hold 15 PSI otherwise you'll be replicating that home made rocket trick - I think retmil46's sprayer bottle sounds a better bet. I can say, however, that you need a really nice big reservoir of compressed air to keep the fluid flowing consistently - I can imagine that there would be nothing more frustrating than lying in the dirt fiddling with bleed nipples whist trying to pump enough pressure to keep those bubbles flowing through (rather than watching them merrily float their way back up your clear bleeding tube into the caliper again).

alabbasi · #21 07-29-2012, 03:58 AM

Quote:

Originally Posted by tbomachines

Here's an idea that I had - take a 2l soda bottle, epoxy in a schroeder valve from a bike tube into the side of it. Drill a hole in the cap and stick a tube into it (sealing it). Grab a spare mc cap or adapter and seal the other end of the tube to it. Put fluid in the soda bottle and pump it to 15psi with a bike pump or compressed air or something and youve got a power bleeder for almost nothing! I haven't built it yet but I'd have to imagine it would work great...sorry if it's a bit hard to follow I'm typing from my phone.

Holy cow! A Motive power bleeder $50. How cheap do you need it to be?

Diesel guys

retmil46 · #22 07-30-2012, 01:35 PM

Quote:

Originally Posted by alabbasi

Holy cow! A Motive power bleeder $50. How cheap do you need it to be?

Diesel guys

I already had all the stuff, besides the sprayer, laying around the house already. Didn't even take a whole hour to rig it up. Why spend $50 to $75 plus shipping when I don't need to?

I did go to Lowes and spend another $15 to get a better-built bleach/chemical sprayer. The one I bought at Wally World was a POS that was missing half the parts, and upon examination was one that had been used and brought back - they'd just resealed the box and stuck it back on the shelf for someone else to buy - didn't even bother taking it back, as they'd probably do the same thing over again to another poor shmuck, just tossed it in the trash.

The one I got at Lowes was an H.L. Hudson bleach sprayer, much better built, Viton seals, easily handles 15 psi, had an extra flat spot molded into the top for adding a pressure release valve. I used that flat to install a tee with a 15 psi gauge and a 1/4" ball valve for pressure release. Already had a 10 ft roll of 1/4" tubing on hand, installed that onto the outlet.

Fianlly figured out where the Mopar parts websites had the reservoir cap for the Jeep listed - they had the entire booster/master cylinder assembly, listed under "Cowl - Dash Components"!

WTF? Are these guys just being purposely obtuse?

Air&Road · #23 07-30-2012, 02:17 PM

In recent years, for mixture measurement on a carbureted vehicle, I have simply welded a bung in the exhaust pipe and screwed in a one wire O2 Sensor. Take the wire into the passenger compartment and connect a DVM measuring DC Volts from the wire to ground. 451 millivolts is ideal stoichiometric. I have a graph that shows the non linear curve for the voltages vs. fuel/air ratio. Works really great for dialing in a carburetor.

Stretch · #24 07-31-2012, 03:31 AM

Quote:

Originally Posted by Air&Road

In recent years, for mixture measurement on a carbureted vehicle, I have simply welded a bung in the exhaust pipe and screwed in a one wire O2 Sensor. Take the wire into the passenger compartment and connect a DVM measuring DC Volts from the wire to ground. 451 millivolts is ideal stoichiometric. I have a graph that shows the non linear curve for the voltages vs. fuel/air ratio. Works really great for dialing in a carburetor.

I would hazard a guess that that's good for your transducer but not for all O2 transducers! Which transducer (as in make and model) do you have?

BAVBMW · #25 07-31-2012, 02:45 PM

Actually, that voltage is for all narrow band Oxygen sensors. Wideband is usually a 0v-5v signal. Most all of the differnces in oxygen sensors is the connector and wiring (length). Heated and non-heated as well. And the heated untis will work without the heater circuit hooked up, they'll just take time to warm up.

MV

Air&Road · #26 07-31-2012, 02:47 PM

Quote:

Originally Posted by Army

I would hazard a guess that that's good for your transducer but not for all O2 transducers! Which transducer (as in make and model) do you have?

No, all of them that I know of have the same electrical characteristics.

tbomachines · #27 07-31-2012, 04:10 PM

Quote:

Originally Posted by alabbasi

Holy cow! A Motive power bleeder $50. How cheap do you need it to be?

Diesel guys

Everything there is free for me, and it'll take about 15 min to assemble. Saves me $50, no harm in that! Fwiw I just resoldered about half the circuit board on a little mp3 player to save $30 on a new one. Guess it's just in me

Emmerich · #28 07-31-2012, 10:51 PM

If you want cheap, get a long piece of hose, hang from the ceiling and attach to bleed nipple. To be safe you could use a small clamp. Open nipple slightly. Pump brake pedal, fluid will fill the hose. Shut nipple, dump hose into container.

I change from blue to gold DOT4 each time so you can tell when it is all flushed.

Stretch · #29 08-01-2012, 04:04 AM

Thanks for the feedback on the O2 sensors Larry and BAVBMW - amazing that they're all the same. I wonder why? I'll have to look into it.

Air&Road · #30 08-01-2012, 07:38 AM

Quote:

Originally Posted by Army

Thanks for the feedback on the O2 sensors Larry and BAVBMW - amazing that they're all the same. I wonder why? I'll have to look into it.

In scientific circles it is called a Lambda sensor. Lambda Sensors, I think a certain category of them, all have the same characteristics. I know nothing about Lambda sensors except that this was pointed out in a detailed carburetor tuning book that I've had for many years.

Googling Lambda Sensor might lead you to what you are looking for.