Front Wheel Cylinder Woe's

[Scooter]

Hi,

I am currently bleeding the brakes on my '57 100-6 restoration project (new system), and cannot seem to get any wheel cylinder movement at the front brakes(one wheel cylinder per brake shoe). Fluid will slowly dribble out of the bleeder screw when I open it, but no more than that. There is no movement at the wheel cylinder whatsoever. The rear brakes seem to be working fine, but the fronts are giving me problems. I believe I read somewhere, that there is a trick to the front brakes, but I cannot remember where I spotted that article.

Thanks for any help,

Scooter

 

[Randy Forbes]

Are your front rubber hoses new as well? If not they could be restricting the flow of fluid through them to the cylinders.
It has been quite a while since I've had to bleed twin leading shoe brakes (now have MKI discs), but I can't recall ever having problems or requiring tricks to do so.

[ 04-06-2003: Message edited by: Randy Forbes ]</p>

 

[Scooter]

Thanks Randy, the entire system is brand new, with the exception of some items that were rebuilt, and bronze unions. Brand new SS lines, rebuilt master, new wheel cylinders, brand new flex lines, etc...

Scooter

 

[Dave Russell]

See if this link is what you are looking for.

https://www.team.net/html_arc/healeys/200301/msg00662.html
D
<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by Scooter:
Hi,
I believe I read somewhere, that there is a trick to the front brakes, but I cannot remember where I spotted that article.
Scooter<hr></blockquote>

 

[Scooter]

Thanks for sharing the link Dave. I'll try the idea suggested by Alan Garrison in the autox archives, but I have already removed the drum on the left front to remove all air (or most of it) from those two wheel cylinders to determine whether that might have something to do with the problem. I'm surprised the push of the pedal doesn't force fluid through the bleeder screw when it's open. If the bleeder screw is open, fluid (or air} should be allowed to flow relatively freely.....

Scooter

 

[Dave Russell]

Scooter,

Yes, fluid should flow freely if you open the bleed screw one turn. How did you verify that there was no air in the cylinders, as you said, if nothing comes out of the bleed screw?

You can try the process of elimination. Start with the connection of the steel line to the rear cylinder, connection of the steel line to the front cylinder, connection of the flex line to the front cylinder, connection of the flex line to the steel line, connection of the steel line to the junction block. Somewhere along the way you should get fluid flow.

Be sure to keep the reservoir can topped up.

When you think that you are at the problem area take things apart & investigate.
D

 

[bob hughes]

Slightly different location but the same process, my clutch slave cylinder on a BJ7 failed and I had to re rubber the piston. I used a long thin bleed tube and elevated it like a hospital drip in reverse to help bleed the system as I was on my own. Firstly, just by cracking the bleed screw the fluid just poured into the bleed tube up to the level of the resevoir, which was then topped up with more fluid, subsequent pumping removed the air and I just let the level steady prior to pumping again. The point is that fluid passed through the master cylinder to the bleed point easily without pumping and I would expect that this should be the same with the brake system, as the master cylinders are identical, admittedly my master cylinders are different from yours. Try removing/cracking a joint on the flexible hose feeding the brake cylinders and see if you can get any thing through with or without pumping as Dave Russell suggests. It sounds incredably like a blockage even if the system is new. Have you checked the bleed nipples to see if they are clear, it sounds as if you can just remove them to check.
Let us know how you get on.

Best of luck, Bob

[ 04-07-2003: Message edited by: Bob Hughes ]

[ 04-07-2003: Message edited by: Bob Hughes ]

[ 04-07-2003: Message edited by: Bob Hughes ]</p>

 

[Scooter]

Hi again,

Thanks for the additional suggestions. I'll privide you with a better description of where I'm at.....quite some time ago (about six months or so), I assembled the system. I had Apple Hydraulics bore and sleeve the master cylinders, and then I rebuilt them using a rebuild kit. They seem to be working just fine. I installed brand new SS lines, installed brand new rear wheel cylinders, rebuilt and installed the front wheel cylinders, and completed the assembly of the entire hydraulic system. About a month or so ago I attempted to bleed the system using the Mighty Vac system, and the rear brakes did just fine. Although, I could not get any fluid out of the front brakes....either side. Since I couldn't figure it out at the time, I decided to move on to other things and deal with it later.

Now is later, and this past weekend I removed the left front drum to get a better look at what is going on. I am getting a free flow of fluid where the SS line connects to the flex line, and when that line is disconnected, fluid rushes out when the brake pedal is pressed. When I open the bleed screw (SS line reconnected) I am getting a very slow dribble. When the bleed screw is open and I step on the brake pedal, the dribble does not increase, and pedal does not go to the floor as you would expect. So there must be a restriction between the flex line and the bleed screw. I haven't investigated the right front brakes yet, but I'm assuming it is the same. Since I rebuilt these wheel cylinders myself, I'm wondering if maybe I did something out of the ordinary to cause this problem. My first thought was that maybe I connected my hard lines to the wrong holes, but I don't believe they could be assembled any other way since the pre-bent short line that connects the two cylinders wouldn't fit any other way.

When I compress each of the pistons I can hear fluid passing back and forth between the two, and when compressing the piston nearest the bleed screw, fluid comes out with no noticable air. I believe there is very little air between the master cylinder and the flex line, but there may be a very small amount of air between the flex line and the bleed screw.

Thanks for any additional suggestions.....

Scooter

 

[Dave Russell]

Scooter,

The flex line connects to the top port of the front cylinder.

The hard line should connect to the bottom port on the front cylinder & to the top port on the rear cylinder.

Bottom port of rear cylinder has the bleed screw.

Now the long shot: Some early cars had a steel ball under the bleed screw on the rear cylinder, (bottom port).

If you interchanged the front & rear cylinders, the steel ball would now be on the top port of the front cylinder & would be blocking fluid flow into the cylinders.
D

[ 04-07-2003: Message edited by: Dave Russell ]</p>

 

[RF Thom]

I had trouble bleeding my BN4 front drum brakes getting all the air out. As noted the bleeder is on the lower port of the rear cylinder. In frustration I decided to read the Bentley manual - it advises to turn the adjusters to lock the shoes outward onto the drum. This forces the brake shoe around and bottoms the piston in the cylinder preventing any air from staying in the cylinder. I then bled the brakes and received a firm pedel.

Regards, Bob

 

[Dave Russell]

Bob,
Since the rear adjusters are positioned on the opposite shoe ends from the wheel cylinder the Bentley manual instruction is correct for the rear brakes.

However, the FRONT adjusters are positioned close to the wheel cylinder end of the shoes & backing OFF the front adjusters will collapse the cylinders the most.
D

<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by RF Thom:
the Bentley manual - it advises to turn the adjusters to lock the shoes outward onto the drum. This forces the brake shoe around and bottoms the piston in the cylinder preventing any air from staying in the cylinder. I then bled the brakes and received a firm pedel.

Regards, Bob<hr></blockquote>

 

[ThomP]

Yet another long shot suggestion...

Are you sure Apple Hydraulics didn't cover (or forget to create) the paths for the fluid to travel into and out of the cylinder? It may be a simple oops on their part. They forgot to open the passages for the ports after sleeving?

Again, it's a long shot, but sometimes. "blue sky" is reality...

Good luck

 

[bob hughes]

OK, so you have removed the flexi from the hard line, now try removing the flexi from the brake cylinder and see what comes through the flexi, reconnect then remove bleed nipple altogether and try that, but look out for that ball bearing, a silly question , have you turned the bleed screw far enoughin the first instance.?

Bob

 

[Scooter]

Hi all,

Thanks for all the great suggestions. This weekend I will have the extra time to work on my front brakes, and I will report back what I find out. Bob....I'll check the flex lines.....

Scooter

 

[Healey 100]

Scooter:

You've gotten a lot a good suggestions. One I have not heard is that there is corrosion or debris around the seat of the bleeder valve. Some of these have a separate ball to seal the valve, and the ball could be stuck to the seat.

There is a catch 22 with these bleeders, if they don't open fully, with air in the system you can't develop enough pressure at the valve to force any debris aside, and just a few drops dribble out.

I suspect your problem is at the bleeder, you may need to fish a wire through it to ensure it is open enough to bleed.

Bill.

 

[Scooter]

Well folks, this is hard for me to report, but my brakes are now working just fine. I'd like to blame it on silicone brake fluid syndrome, but as it turns out, some knuckle-head (yes, that would be me)

accidently left the little steel balls inside of the wrong two wheel cylinders.....just like several of you pointed out could happen. All I can assume is that I was experiencing an early senior moment.

Scooter