Hi Everyone,

I hope someone can either reassure me that my bleed job is okay, or tell me what I can do to make it right.

I installed lengthened brake lines front and rear recently, and then this evening was in the process of bleeding the lines.

I purchased a hand vacuum pump from Harbor Freight (the same model sold by NAPA) and followed the instructions that came with the vacuum pump, along with the bleed sequence provided in the Jeep electronic manual that I have.

The concern that I have is that I can hear sounds similar to cavitation as I open each bleed fitting and fluid (and some air) are drawn into the hand pumps reservoir. I have pulled quite a bit of fluid through each bleed fitting.

I have actually performed the bleed process twice, and the sound continues.

I am thinking about doing a standard bleed with someone working the brake pedal; but, I would prefer not to do that if the brake system is okay the way it is.

Any help that can be offered for the following questions would be appreciated:

1. How can I be certain that the sound I am hearing is simply the fluid leaving the bleed fitting and entering the larger ID tube which leads to the vacuum pump?

2. Nothing in the bleed instructions said anything about compressing the calipers (nor was anything said in the Jeep manual); but, I believe I read something somewhere in this forum where there was talk about compressing the calipers. Is this something I need to do?

3. If I do the bleed by having someone pressing on the brake pedal, will that likely have different results (i.e. will there be no air bubbles)?

4. If I do the bleed using an assistant, should the Jeep be started to take advantage of the system power/ABS, or, is it better to have pressure built up using only the pumping of the brake pedal?

5. Should the bleed line from the fitting be held up to collect fluid in the line (to be able to watch the air bleed by), or should it run lower than the bleed fitting?

It has been a long time since I bled brakes (like on my '67 Belair), so my confidence level could use a boost.

Any advice would be appreciated. Sorry if these are pretty basis questions.

Thanks

Jeff

 

I had to have a brake shop do mine since my rear pistons were jacked up. Anyway, I was loitering out back watching and talking with the tech while he did the work. I was surprised how he did it and I asked about it... All he did was pump up the pedal to get the pressure up, then he opened both the rear bleeder valves. Oh yeah, the cap was off the master cylinder at this time too. The valves dripped somewhat slowly and if you put your finger over them, the fluid would bubble a little showing there was still air in them. He left them open for 2 or 3 minutes until they dripped quite a bit faster and couldnt make any bubbles. I would say that you have it right as long as you dont have a soft pedal. Not sure on the noise you are talking about though...

 

Good info!

 

I should have just waited on my wife to bleed the brakes. She had already gone to bed so I thought that using the vacuum tool would work well in her place.

It took a lot longer. And, I'm pretty sure the air was out of the lines by the time she was able to help me bleed the lines the conventional way. (If I had a bigger vacuum reservoir, it would probably work great.)

(I originally looked for a write-up; but, I couldn't find it. I thought that it would be in the write-ups section of the forum. Now I know better (maintenance).)

Thanks for all the feedback.

Jeff