1-man Hydraulic Bleeding Kit for those with Air Compressor!
This is a DIY cap-hose combination, to bleed the hydraulic system using an existing Air Compressor.
In theory, you can use "Motive Power Bleeder", which is nothing more than a modified garden sprayer bottle. However, it costs around US $50 or so.
But for those who already own an air compressor, you can do the following DIY, this way you:
- Can invest minimally using my DIY (about $15 total)
- Do not have to clean the Motive Bleeder after the job. Also keeping the Motive Bleeder Bottle clean for the next 2 years (until you beed again) can be a challenge (dirt collecting inside the bottle etc.).
- Using my DIY cap-hose combination, you simply bleed and then store the DIY cap-hose combination away after use. Just use a ziploc bag to cap both ends and tie it so dirt does not get in this device.
- Brake Fluid is very corrosive to paint work, so wipe off any spill on paint work ASAP.
- Use a small funnel to pour brake fluid into the reservoir to avoid spill.
- Wrap the area around the reservoir with some rag to absorb any spill.
- The Air Compressor: use minimum 10 psi, max 15 psi. Do NOT exceed 30 psi (risk of damage to reservoir although I do not know for sure what pressure it takes to rupture the reservoir).
- Do not ever allow air to enter the hydraulic ABS system, because once air is inside the ABS Modulator, it is very difficult to get rid off. If you allow air to enter the ABS Modulator, then you need to visit the dealer so they can use their computer device to bleed the air out of the ABS Modulator. Now you are talking big expense!
- If you fill Brake Fluid to within 1 inch of the cap, you can safely bleed using the standard small catch container as in the pic (sold at many auto parts store) twice before refilling the Brake Reservoir again.
- When in doubt, stop and check the reservoir to be sure it does not fall below "Min" level.
- Do this on a dry day so moisture from the air does not enter the compressor. Avoid rainy days at all cost!!!
- I have a 1998 BMW 528I and 1998 Volvo V70, with both using ATE Brake System. So buy the standard 45-mm ATE cap from FCP Groton (or local Volvo dealer). Just get the cap from a 1991 Volvo 240 or 740. Back then those caps did not have Brake Fluid Level sensor. It was a plain simple 45-mm cap.
- This 45-mm cap can be used to bleed hydraulic system in any car with ATE reservoir such as: MB, BMW, Audi, VW, Volvo, SAAB etc. Check to be sure if using it on other cars. Japanese cars use different caps. Here is what it looks like:
1. To make my DIY cap-hose combination:
- ATE Brake Reservoir Cap from FCP Groton or local Volvo dealer; Volvo PN 1272107, used in many Volvo cars since 1960's through 1990's ($5.00):
- Compressor Hose ($6-7 at my local Menards hardware store, or Harbor Freights etc.): Edit you may not even need this hose (see Edit below).
- 1/4-inch nut ($1.00)
- 1/2-inch washers ($1.00)
- Drill a 1/2-inch hole in the ATE cap and clean any debris.
- Use the Air Hose Male end and insert into the cap, washer on both sides.
- Small bead of Silicone under each washer and the hose male end's threads.
- Tighten the 1/4-inch nut hand tight.
- Let the Silicone Caulk cure for one day before using it.
2. To bleed:
- Open the bottom drain valve of the Air Compressor and turn the Air Compressor on to expel any water inside the Air Compressor. Then close the bottom valve.
- Keep air pressure within 10-15 psi (this works best for me). Do NOT exceed 30 psi!
- Using a Turkey Baster, suck out as much old brake fluid from reservoir as possible.
- Using a Small Funnel, add Fresh Brake Fluid until it is about 1 inch from the top. Avoid spilling or overtopping!
- Attach the cap-hose combination.
- Connect to Air Compressor using the quick disconnect.
- Keep air pressure within 10-15 psi!!!
- Start bleeding, remember you can bleed about 2 small containers before you need to refill.
- To refill reservoir, disconnect air hose at "quick disconnect", refill reservoir to within 1 inch of the top. Re-connect hose.
- For each car, I use about 70-80% of the 32-Ounce (946 mL) Brake Fluid Bottle. I use Valvoline Synthetic Brake Fluid (DOT 4).
If you already have a hose and quick disconnect (you should) from your air compressor, then no need for the another yellow air hose as in my pics above.
You can simply buy a 1/4" NPT fitting for $0.50 (or buy a kit with different air fittings for $3.99 at Harbor Freight) and attach it directly to the brake cap:
Once you have done this using Air Compressor, you may throw your Motive Bleeder away!
Last edited by cnn; 08-27-2009 at 11:20 AM.
Very nice job!
I tend to keep the fluid pressure at 10lbs maybe 12lbs as I have had the brake fluid resivoir pop off the master piston on my 533i at 17 lbs. It had new, soft retention grommets which released under pressure. 10lbs seems to work just fine.
Make sure your compressor has an inline filter on it so you're not introducing any contaminents into the fluid.
One other thing I do when completly changing fluid, I pull as much brake fluid as I can with a pull pump/baster. Then to get the other half of the reservoir's contents, clean as much dirt/gunk away from the bottom and sides of the reservoir, place rags under and around the reservoir then carefully pull the reservoir straight up with a little wiggeling. be sure to not drop and dirt into the master cylinder intake grommets.
I pull the reservoir to get the last 4 oz or of fluid and contaminents that settle to the bottom of the reservoir. Away from the cars, I put clean brake fluid in the reservoir and swish it around and drain. Repeat till the reservoir is free of sediment. Wipe down the outside of reservoir, check for cracks or deterioration. Good time to check/replace the grommets that seal the reservoir and master cylinder. Then replace the reservoir and refill with clean brake fluid.
Thanks for writing this DIY up!
Last edited by BlackBMWs; 08-27-2009 at 10:55 AM.
1999 540it - Schwartz II/Sand Beige, style 5 rims, Conti DWS 235/45 tires, Billy HD/Sports, Stoptech S/S BL, F1 Pinacle 35% tint, Zionsville Cooling kit
1998 318ti Cali Sport - Schwartz II/Schwartz Anthratz, staggered style 23
1997 318ti Sport - Schwartz II/Schwartz Anthratz, staggered style 68 ,
1995 318ti Active - Alpineweib III/Schwartz, squared style 32
1994 325i - Bostongrau/Tan, Billy Sports, H&R springs
1991 318ic - Schwarz/Anthratz Stoff, Bilstien HD, Z4 3.0 SS, Magnaflow, S/S Stress bar, x-brace, M20 FW, Elipsoid/HID, K&N
1995 318ti Sport Schwartz II/Schwartz Anthratz - Sold
1985 635CSI - Schwartz\Sand - Sold
1984 533i "Max" - Schwarz/Schwarz, - Sold
1984 318i - Champagne/Tan, Stock - Sold
Nice! anyone want to buy my motive power bleeder?
I got rid of my Motive Bleeder a long time ago! The Motive Bottle can collect alot of dirt/moisture between bleeding jobs. Plus the pump seal can harden with time.
You can see with my DIY, after the bleeding is done, there is nothing to clean.
Just wipe the ATE cap and store it in a Ziploc bag for the next time.
For each bleeding job, all you need is to re-fill the reservoir maybe 3-4 times and that is it. The re-fill process is very quick.
For those grease monkeys who still hesitate: go get yourself an air compressor, it is good for many things: tire inflation, air tools for home remodelling projects, brake bleeding.
If you have no room in your garage, you don't need a professional huge air compressor, a pancake type (approx. $50) is good enough for many jobs around the cars/houses:
Last edited by cnn; 08-27-2009 at 11:10 AM.
This is a very good suggestion as I know my compressor adds some moisture when compressing the air (I see some dripping when I release the pressure from my tank). What type of filter do you use and where do you get them?
Originally Posted by BlackBMWs
Originally Posted by fudman
Every compressor uses fresh ambient air to compress, so any moisture in the air will be condensed into water. This is why in my DIY I mentioned that avoid rainy days. But even on sunny days, there is some moisture in the air too. The water condenses at the bottom of the tank, this is why you always drain the tank after each use and leave the drainco_ck open a bit so any water will get out.
I think this is the Air Filter that BlackBMWs referred to:
Last edited by cnn; 08-27-2009 at 12:39 PM.
either that or a dessicant filter like you would use on a paint gun.. the media inside absorbs most ifnot all the moisture of the air passing through it and would work great for this application
Great idea, got some parts on the way to make one of these. Quick question. On your air compressor picture, you show having the tank pressure at 10-15psi. I have a similar compressor with the two gauges, one for the tank and one on the outlet regulator, but I'm not sure how to regulate the tank pressure - it always goes up to full pressure 125psi and then I just dial in the outlet pressure.
Is that a safe way to do this? I think with a 10psi tank pressure the compressor would be running all the time.
Glad you asked!!!
Originally Posted by cpikel
A typical compressor has 2 gauges:
1. One gauge shows the actual pressure such as 90-100 psi, which is typically used for Power Tool (Nail Guns, Air Ratchets etc.).
This is factory settting and I think you cannot change this (whatever it is like 90-100 psi or so).
2. The 2nd gauge is the regulator, let's say you only need 60 psi.
So you dial it to 60 psi and only 60 psi goes to the hose.
However, in this situation of brake bleeding, anything more than 25-30 psi, you risk blwing up the reservoir, seals and other stuff.
So, this is what I do:
- Drain the compressor of water first.
- Turn the compressor on for only 15-20 sec to build it to 10-15 psi. Then I turn off the compressor and bleed the brake. Believe it or not this 5-gallon compressor at 15 psi is enough to bleed 2 cars.
I don't build the tank to 90-100 psi, this is because in case the regulator malfunctions, you end up with expensive problem of brake fluid all over the place etc.
Last edited by cnn; 10-19-2009 at 09:32 AM.
For those of you who have another car other than the E39, if you cannot find the factory Cap to fit, there is another way to make the Universal Brake Bleeder Cap for $8.00 total.
1. Universal Brake Bleeder Cap Parts List (See Picture):
- Plumbing PVC Drain Cap 3": $1.50
- Standard Air Adaptor: $0.90
- 1/4" FIP x 1/8" FIP Reducer: $1.00
- 1/8" Lock Nut: $1.00
- 1/8" MIP Pipe: $1.00
- 3/8" Washer: cheap
- Teflon Tape, Rubber Gasket and Silicone Caulk
- Go to any local Ace Hardware store, they have everything you need there.
2. To make Universal Brake Bleeder Cap (See Picture):
- Drill a 3/8" hole on the side of the cap (Do not drill on the top, you need to leave the top alone for the U-bolt to clamp on). Enlarge the hole a bit so the Pipe goes through snugly.
- Using Teflon Tape, Assemble the Standard Air Adaptor ---> 1/4" FIP x 1/8" FIP Reducer ---> 1/8" MIP Pipe
- Now slide the Pipe into the PVC Cap just a bit, then apply some silicone caulk on the thread, then push the whole Pipe into the cap. Then install rubber O-ring and washer and Lock Nut. Tighten it snug.
3. The Set up with U-bolt (See Picture):
- For comparison, on the Right Side is the 45-mm "ATE" Brake Cap I use on my Volvo, BMW but this can also be used in any European cars with ATE Brake Cap (Volvo, SAAB, BMW, MB, VW, Porsche, Audi etc.)
4. The Set up in my 2007 Honda Odyssey Van (See Picture):
- Air Compressor "Pressure Regulator" set at 15 psi max.
5. 2007 Honda Odyssey Van Bleed Screw (See Picture):
- Bleed Screw is 10-mm for both Front and Rear Brakes.
- I use Lisle Brake Container "Item 19200" ($6.00 at local auto parts store). It probably holds about 2 ounces of fluid:
- When filling the 2007 Honda Odyssey Brake Reservoir to the Top, if you bleed the brake using the Lisle container up to 80% of the container, then one Reservoir Fill is good for 2 containers.
- Whatever you do, do not let the Brake Fluid level get below 1 cm under the "Min" mark. Do not ever allow air in any car with ABS because once air gets into the ABS Modulator, it is a headache to purge the air out of the Hydraulic Actuator (go to dealer etc.).
- Air Compressor Main Pressure may be at 20-30 psi but the Regulator must be set at 15 psi max.
- Tighten the U-bolt nut by hand only, you may use a wrench but be gentle, do NOT over-tighten the U-bolt. All you need is snug. A little leak is OK because this Universal Cap is not as tight as factory cap. But you will find out that a little leak is no big deal because with the air compressor, all you have to do is to crank it up a bit here and there.
- After the entire brake bleeding job is complete, if your Brake and VSA light is on in the instrument cluster, don't panic! This is because during brake bleeding process, when the brake level is below Min level, the Brake Fluid Level Sensor sends a signal to the computer. Even after you fill the brake reservoir later, the signal is still there. After driving 1-2 cycles, the light will be out.
- Enjoy the Universal Brake Bleeder Cap.