that has ABS. In particularly concerned about getting air into the ABS system, and have read something about shorting 2 pins on a diagnostic connector to open the ABS valves.
Any ideas? Note, pics help! You can tell me a million times, but one pic=1000 words! ;)
I would think you'd be OK just opening the system one corner at a time and bleeding/re-filling before opening the next corner.
but, interested to see more replies.
I would think you'd be OK just opening the system one corner at a time and bleeding/re-filling before opening the next corner.
but, interested to see more replies.
Above all, be careful not to let the reservoir level get too low at any time.
Yeah, that I found. Seems the worst case is if the reservior runs out and a bubble gets in the ABS. It was dangerously low when I bought the car.
I don't know if this will work on a Subaru ABS, but with the caliper away from the pads, pump the brake to extend the caliper piston an inch or two, and then use a C-clamp to push the piston back in, reverse-bleeding the ABS controller of any air bubbles in the process.
For the 96 Outback, I suggest:
With a clean turkey baster, empty the master cylinder reservoir. This reduces the brake pedal pumping time while bleeding; see below before jumping to conclusions.
If you are a neat freak, remove the reservoir and wash it with hot water and detergent. You may use small ball bearings to dislodge any brake fluid leftovers from reservoir walls. Rinse it thoroughly with clean water. Use a hair dryer to evaporate all the water and moisture left inside, do not get the reservoir too hot. I have done this and works great.
Reinstall the reservoir and fill it with good quality brake fluid. You can go into exotic brands and prices, but I am happy with the valvoline synthetic brake fluid.
Get a length of the right diameter, clear PVC hose, (3/16 i think), that it reaches from the highest bleeder to an empty jug, i would say about
20 inches long or so. Drill a lil hole on the jug cap so the hose fits snugly through the cap. Drill another hole for venting purposes.With a helper, to pump the brake pedal and keep the fluid level in the reservoir, start by bleeding the wheel closest to the ABS unit. Bleed it until the fluid comes as clear as it is in the master cylinder reservoir.
Establish a code with the helper and the person doing the bleeding. The bleeder will call "open" when the bleeder in the wheel cylinder/caliper is open, signaling the helper to push the pedal, at a moderate speed, until it gets to the lowest position. Then the helper calls "bottom" for the bleeder to be closed. Calling "closed" signals the helper to release the brake pedal at a moderate speed. Repeat until clean fluid, free of bubbles is coming out through the clear pvc hose. If bubbles persist, pump the brake pedal a few times with the bleeder closed, keep it pushed under pressure and then open the bleeder. After a few repetitions, the air should be gone for good.
Only in cases when dirt has been allowed to go in the master cylinder / brake system, and the dirt is stuck in the check valves in the master cylinder, I use the reverse bleeding procedure. In that case you charge a high pressure oiler such as HarborFreight.com's 66350 with clean break fluid, connect it to the open bleeder and pump fluid back into the reservoir. Empty the reservoir with a super clean turkey baster. I do not recommend to use this system all the time, because lots of dirt gets trapped in the calipers and wheel cylinders. This dirt will be forced into the abs and master cylinder, not such a good idea. Some cars cannot be bled correctly without using the reverse bleeding. Subaru has not been one of those.
Remember, cleanliness is of the utmost importance.
Good luck,
AS
hachiroku wrote:
Just to add:
You might want to put a block of wood under the brake pedal to keep it from travelling more than it normally does while braking. This prevents the pedal from bottoming out.
In normal use, the seals in the master cylinder wear away at the bore, leaving a tiny lip on the bore at the end of the travel stroke. When you press the brake pedal all the way to the floor during bleeding, that tiny lip and the unworn bore beyond it can damage the seal, resulting in an internal master cylinder leak shortly afterwards. (The brake pedal will slowly fall to the floor while stopped at a light.)
Actually, I made up a rig so I can bleed the brakes all by myself. It works well, but I also use a broom handle to depress the pedal, close the valve and then release the pedal. Repeat as required.
I wish the kids were still home...:D
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.