Bleeding Brakes tips?

[SCguy]

When ever I'm bleeding brakes it seems that I always get air sucking through the threads of the bleeder valves as I loosen them to pump fluid. Is this possible? I seem to have the same trouble whether I am just having someone pump the brakes or if I use my Minivac. Is there a trick? /ubbthreads/images/graemlins/confused.gif

 

[Alan_Myers]

Hi Larry,

The biggest single improvement I can suggest is to replace all the bleeder valves with Russell Speed Bleeders or similar. These have a one-way valve built into them, and the threads are coated with a sealant.

Speed Bleeders make the job far, far easier. They cost about $10 a pair, so $20 for front and rear. (You might eventually want one on the clutch hydraulics, too.) You can find them at local auto parts stores, and online at places like www.summitracing.com.

Speed Bleeders are made in various size/thread/length. On the front calipers of a TR4, I seem to recall you need 3/8-24 x 1.5" (ISTR originals were 1.25", but I don't think that size is as widely available). On the rear, I think 3/8-24 x 1.0" will work (but longer can be used and might be more convenient).

Start the bleeding process at the corner farthest from the master cylinder. That's one of the rears, but I think which one varies from live axle to IRS models... I know it's the LH rear on TR4.

Note: I have used Locktite thread sealant (comes in a small tube) on the threads of old standard bleeder valve successfully, to help keep air from getting drawn in. This stuff eventually all gets wiped off or squeezed out, though, and it sets up to some degree over time (good to keep the valve from loosening, but bad if the corners of the nut are rounded and worn).

Use of teflon plumbers tape is not generally recommended because of a real danger of getting bits and pieces into the hydraulic system where it might block something or cause other problems, but done very carefully it can work too.

Frankly, I've never had much luck with MityVac for this job. An olive jar partially filled with brake fluid, a short length of tubing and careful pumping of the pedal by an assistant seems the best method... at least for me. Tell the assistant to operate the pedal slowly both directions and never push the pedal completely to the floor. In theory, with Speed Bleeders you should be able to do it as a one person job. However, that means climbing under the car to loosen, then out to push the pedal, then back under to tighten.

You probably already know... Watch the fluid level in the master cylinder reservoir very carefully. If it gets too low, there will be air drawn into the system.

Some day I'm going to invest in a proper brake bleeding system like most auto repair shops use!

Hope this helps!

/ubbthreads/images/graemlins/cheers.gif

 

[tomshobby]

Please don't take this wrong, I not trying to be a SA here, just making sure you know.

Push pedal, open bleeder, close bleeder, release pedal. Repeat as needed until no more air comes out.

If starting with new lines or system that has had a major fluid loss you may have to cycle through the wheel cylinders more than once.

If air continues to get in system it may be from a small leak in the system, such as a rusted pin hole or leaking cylinder cup. Or a bored helper releasing the pedal a small amount or too soon. I know about the helper part, when I was a kid that was my part and I used to get in big trouble.

 

[CraigFL]

I used to hate bleeding brakes and clutches until I made my homemade power bleeder system. It was started with the parts from my broken MityVac. I modified a master cyl cap -- drilled it for a 1/4" barb fitting. I run tubing from it to my one quart brake fluid reservoir--the side with the tube that goes all the way to the bottom. Then I pressurize the reservoir with my air compressor -- 7 to 10psi (use a tire if you need to). Careful with the pressure, the M/C won't like much over 10psi!

Now, all you have to do is open & close the bleed nipples. No worry about running out of fluid unless you're doing a complete flush--then watch the level in the reservoir after each corner. You can open the nipple wide and watch for the clear(no bubbles) fluid.

 

[SCguy]

Does anyone know which Speed Bleeders fit toyota front calipers? Summit's book don't go back that far.

 

[Alan_Myers]

Hi Larry,

I'm afraid I don't know what size fits Toyota, but I'd guess it's metric. Just about any parts store that sells the calipers should know, or be able to check for you.

The SC is the same as the original brakes, 3/8-24. For length, I imagine 1.0" to 1.5" would work.

Pretty easy to check any of these if you've drained the hydraulic system. Just pull out the bleeder screw and measure with a thread gauge. Or just take the screw to a hardware store that sells nuts & bolts and try on for size to determine what it is, if you don't have any thread gauges (note: if you have taps and dies, you can make your own thread gauges).

If there is still fluid in the system, you'll lose a little pulling the bleeder screw all the way out, but can temporarily block it with any bolt with the correct size & thread. That's useful if you want to take the old bleeder screw along with you to an auto parts or hardware store. (A 3/8 NF bolt will work on original TR4 brakes front and rear, and the SC.)

/ubbthreads/images/graemlins/cheers.gif

 

[martx-5]

[ QUOTE ]
Does anyone know which Speed Bleeders fit toyota front calipers? Summit's book don't go back that far.

[/ QUOTE ]

I assume that you are talking about the four piston Toyota calipers. I'm putting them on my TR3, and the bleeders measure M10 x 1.0. They are about 33mm overall length.

Edit: https://www.speedbleeder.com/size.htm has them. Their # SB1010 would be the ones to get. I did a quick look on Summit's site, and the only metric size I saw was M8 x 1.0.

 

[mailbox]

[ QUOTE ]
Push pedal, open bleeder, close bleeder, release pedal. Repeat as needed until no more air comes out.

[/ QUOTE ]

Hey Tom,
It just amazes me how complicated we want to make something so simple. I have bled brakes for over 20 years with the pump up, open bleed valve method and have never had any trouble. /ubbthreads/images/graemlins/grin.gif