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Brake bleeding question
https://slantsix.org/forum/viewtopic.php?t=46174		 Page 1 of 1
Author:  Rob Simmons [ Wed Aug 31, 2011 12:25 pm ]
Post subject:  Brake bleeding question
I was bleeding the brakes on my Dart last night. It has new Wilwood disc brakes on all four corners, new master cylinder, proportioning valve, line loc...

Things were going well until I went to bleed the left front caliper.

The fluid comes out like it had been through a blender! :shock: Tons of tiny bubbles that don't clear up with subsequent bleeds. After it sits in the drain bottle for a few minutes it clears back up.

Is there a good way to determine where the air is getting into the line?

Obviously I'll go back and tighten everything and try again, but wondering if there is a "trick of the trade" on pinpointing issues like this.

Also, the front Wilwood calipers have two bleeder valves (inner and outer). Not sure if there is a specific procedure for bleeding them. I just start with the outer and go in...
Author:  olafla [ Wed Aug 31, 2011 3:00 pm ]
Post subject: 
Can I ask if you bench bleed the master cylinder first? If not, do your self a big favour, and start all over again, this time bench bleed the master cylinder before anything else, the only way to get rid of the bubbles. Takes it's time, but it is the only 'good' way to do it.
I am sure Wilwood has the instructions for it somewhere.

Olaf.
Author:  emsvitil [ Wed Aug 31, 2011 4:14 pm ]
Post subject: 
Wrap some teflon tape around the bleed screw threads.

Air can sometimes slip past the threads when you crack the bleeder open.
Author:  Rob Simmons [ Thu Sep 01, 2011 6:41 am ]
Post subject: 
Thanks for the replies.

I believe the master cylinder was bench bled before it was put on. A friend of mine did the brake work while I was overseas.

I stopped by the garage on the way home last night and looked at it again. I took both front brake lines loose. They are braided lines with chromed ends that can be a pain to get tight. The left front one looked like it had not been seated very well.

I may need to bench bleed the master cylinder again though. Neither of the front lines gravity bled when I took them loose. Nothing at all. When you have someone pushing the pedal to bleed the brakes you get fluid out of the bleeder screws... :?
Author:  WagonsRcool [ Mon Sep 05, 2011 7:46 pm ]
Post subject: 
Before pulling the master cylinder try loosening the line nut for the front brakes & see if fluid "gravity drips" there. I wonder if the pushrod or something is preventing the master from fully releasing / uncovering the compensation port. The front calipers should gravity bleed with bleeders open & m/c lid on loose.
Author:  Rob Simmons [ Mon Sep 12, 2011 11:31 am ]
Post subject: 
I started to fiddle with it again the other night. I thought I'd put some teflon tape on the bleeder screws and bench bleed the master...

I started with teflon tape on the left front... And snapped the head off the bleeder as soon as I started to tighten it back up! :x

Other things going on at the moment, but I'll jump back on the Dart shortly and report back.
Author:  the_shadow [ Mon Sep 12, 2011 12:03 pm ]
Post subject: 
Quote:
And snapped the head off the bleeder as soon as I started to tighten it back up!
Sorry to hear that! Just FYI you don't need to make bleeders very tight at all usually, slightly more than hand tight should do.
Author:  Rob Simmons [ Mon Sep 12, 2011 1:19 pm ]
Post subject: 
Thanks. It wasn't the small 1/4" bleeder that broke. (Been there,... Done that! :lol: )

It was the larger 7/16" 'bleeder' that the smaller 1/4" one fits into on these Wilwood calipers. I'll be swinging by a local speed shop hopefully today to see if they have them.

If it had been the smaller one I could have fixed it that evening. I was able to get it out with a bolt extractor. :D

Here's the thread about the car in question: http://www.slantsix.org/forum/viewtopic.php?t=43876

More to follow...
Author:  Rob Simmons [ Thu Sep 15, 2011 9:18 am ]
Post subject: 
I got a set of replacement bleeders for my Wilwood calipers and put them in last night.

Apparently the bleeders I had have had issues with breaking, so Wilwood changed the design to a more beefy one.

I have some pics to share, but will have to wait until I can elbow my way onto the home computer. :lol:

I also bought a MightyMac vacuum pump brake bleeder so I don't have to wait for a "willing foot" to help me bleed brakes. It worked OK, but I may have one of the boys help me re-bleed them anyway. :roll: :lol:

I'll check this evening to see if it held the pressure. I'm hoping the issue was just that one bleeder being cracked (fingers crossed).
Author:  Rob Simmons [ Thu Sep 15, 2011 7:43 pm ]
Post subject: 
Well, it still has pedal pressure after 10 hours... :D

Here's the pic of the bleeders. Left is the broken one, middle is the new beefier style and then an unbroken one on the right.

Image

Here's what the caliper looks like with the two bleeders. Once I get these little issues sorted out I hope to put these brakes through their paces on an autocross or road course! :D

Image
Author:  Rob Simmons [ Mon Sep 19, 2011 12:39 pm ]
Post subject: 
I've driven the car a couple times now and no brake issues yet. :D

Apparently, that one cracked bleeder may have been the issue all along... :?

I did re-bleed the master with it in the car. All calipers do gravity bleed well now. :wink:
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