Bleeding Brakes

[Bert]

Last Saturday, I flushed out the old brake fluid in my 1972 car and decided to try the Pro Motive Power Bleeder.

http://store.motiveproducts.com/shar...unt2=454505562

I was hoping this kit would take less time and I wouldn't have to bother my wife to "pump and hold"

Well, the cap leaked and spilled a little fluid. But I was able to catch it before it touched the paint. A hassle nonethless.

One important step that is not given in the instructions is to cap off the overflow tube BEFORE you start pumping! Ask me how I know.

Then I broke off one of my rear brake bleeder valves. Luckily, I was able to get a hold of Will at Classic Speed and Parts.

http://www.classicandspeedparts.com/

He had the valve in stock and I was able to finish the project on Saturday rather than waiting for the parts on Monday. Great customer service and he knows our cars. Thanks Will!

I read about Speed Bleeders on Pelican. Has anyone tried this method for bleeding brakes? Sounds easy and less messy.

http://www.speedbleeder.com/

Any advice?

Thanks,

[jameshtaylor]

On an early car, try the system everyone used for the first 40 years people used hydraulic brakes, gravity. No expense, no leaking fluids, nothing to drip on its shelf while taking up valuable space in your garage. Gravity will let you bleed your brakes easily in less than 30 minutes without an assistant, without spending more than $5 on equipment, and without causing any undue stess on the master cylinder. My 73 & 74 lack hydraulic clutches so I don’t know if this procedure can be adapted for use with non-mechanical clutches.

You will need: brake fluid, six or seven feet of clear plastic tubing sized to fit snugly over the nipple on the brake caliper (mine uses 3/16” internal diameter tubing but check yours), and an appropriate small box wrench to open & close the bleed valve. (Sears has small 6 sided combo wrenches which are useful for recalcitrant cases; the bleed valves on my cars are 7mm and 9mm, some may be 8mm.)

Here’s the procedure: raise the car, support it on jack stands or wood blocks, and pull the wheels so you can get at the calipers. Or do one wheel at a time if you want.
Loosen the brake fluid container cover in the trunk.
At the first wheel, fix the plastic tubing so it hangs straight down (from your garage roof or door or even a stick) to the caliper. Slide the box wrench over the nipple, slide the plastic tubing over the nipple, and open the nipple with the wrench.
Watch the fluid rise in the tubing until it reaches the height of the brake fluid reservoir in the car, maybe 15 inches. This will take 3-4 minutes. Tap the caliper a few times with a rubber hammer or block of wood if you want. Watch the tubing for bubbles, especially when you first open the valve. A flashlight held behind the tubing will reveal all. If they keep on coming after the level in the tube has risen 12-15 inches, close the nipple, remove the tubing, drain the fluid in it into a paper cup, and repeat. Assuming you are bubble free after a 12-15 inch column of fluid has drained into the tubing, however, do this once; tighten the valve, pull the tubing off while holding a paper cup to catch the fluid, and move on to the next wheel.
Keep an eye on the fluid container and replenish the brake fluid when it's down more than an inch.
Do all four wheels, replenishing the fluid if it gets down too far.
You are done.
Gravity has done all the work. You cannot damage your master cylinder with this technique, and you don’t need a helper (if you have a garage or a tree or can rig a stick to hang the tubing from.) The process should take you about 5 minutes per wheel once the car is up and the wheels are off.
Forget the idea that there are bubbles all thru your lines and that pressure will somehow push them out but not the fluid. A pressure bleeder only moves any bubbles and fluid thru the lines more quickly. But they travel together. So gravity will do the job perfectly if time isn’t the object.
Forget also the notion that the pressure generated by your brake bleeding kit will somehow give you a harder pedal. You can’t increase the pressure inside the system any more than gravity allows; if you could the fluid would compress when you applied the brakes and your pedal would approach the floor.
This process works well because nearly all the bubbles generated by driving are found at the very top of the caliper near the bleed valve…where they concentrate when generated by heat. (Any 5 year old child knows bubbles don’t move down in a liquid, so they don’t flow down to the bottom of the caliper then across the hard lines and back up to the master cylinder. If they did, they’d escape from the master cylinder reservoir into the atmosphere anyway.)
Depending on how much fluid you withdraw each time, you will find that the fluid is fully replaced every 10-15 bleedings. I track my car 5-6 times per year; bleeding this way pretty much replaces all the fluid over a couple of years, as recommended by many experts.

[304065]

Jim, outstanding explanation. That's what I use for the race car, no danger of spraying fluid and keeps waste of the Castrol $RF to a minimum. Nice.

[68911USA]

That is absolutely fantastic! (Of course, it takes very little to impress the guy who first installed all his brake calipers with the bleeders pointing down towards the ground...duh.) All I am waiting for are the two new master cylinder feed line grommets to arrive (thanks, Pelican) and then I am definitely headed to Ace hardware to buy seven feet of tubing! Hopefully, no more leaks and I'm ready to pull this car out of the garage for the first time since last October.

[jhora]

I read about Speed Bleeders on Pelican. Has anyone tried this method for bleeding brakes? Sounds easy and less messy.

I have used the speedy bleeders...they work fine...easy for one person....I like Jim's method...

[911pcars]

James and others suggestions:
Exactamundo.

Bert,
Give me a call. I have the plastic tubes you will need. I bleed all four wheels at once. You supply a can of BF. Sell the Motiv tank. Saves storage space; not needed.

Here's a "professional" BF catch can from HF. the built-in magnet helps suspend the bleed line above the caliper. The container catches old system fluid.

Sherwood

[Bert]

Hi James,

Thanks for the detailed procedure. I will try your method the next time.

Sherwood - I have enough tubing

Anyone want to buy a brake bleeder

[Jrsully]

Rehashing an old one here, is bench bleeding a new M/C advisable or can I just install it out of the box.? Replacing entire brake system on the 71 and stuck on whether I should do this or not. Plan on doing a gravity bleed (as mentioned above) then have a Motive power bleeder standing by if needed. Any help appreciated

[edmayo]

I have never bench bled one. Usually just install and bleed at calipers,,,,,but if i find a system to be stubborn I may loosen the brake lines at the M/C and pressurize until fluid comes out past fittings, then retighten and move on.

[Jrsully]

Thanks very much Ed, good info. Are you a fan of the gravity bleed method.?