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bleeding the brakes on a BN1

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bighealeysource

bighealeysource

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Hey all,
Another question from your South Carolina Healey nut.
I finished redoing my brakes and in process of bleeding
them. Thought I would get smart and bought one of those
pressure bleeders that you hook up to the bleeder screw
and force any air through the system and out the master
cylinder. Well, works great on the rear brakes but the
front brake bleeder screw has the small ball bearing in
the screw which acts as a valve. Guess what, won't allow
me to try to force fluid up through it as obviously it is
"seating" and closing off the bleeder screw. Know I can
bleed the front brakes the old fashioned way but could I
just remove the ball bearing as did check and can screw the
bleeder screw down to shut off the flow of brake fluid ?
I understand that it is a check valve probably to help keep
dirt, etc from entering the brake hyd system but like most of
us, this BN1 will not be seeing any inclement weather unless
I get caught in the rain.
Thanks,
Mike
 
I think what you have are after-market bleed screws made to simplify bleeding. They allow you to leave them open and pump the master cylinder without sucking air back into the wheel cylinder. once the system is bled, they have no special function. Take the ball out or replace them with common bleed screws.

Or, use them as intended. I've never used them but some people swear by them. I will say that bleeding the brakes on a BN1 is a (censored). I'm still struggling with mine. I'd be working on it now except I decided to give the chief pedal-pumper (my wife) the day off since it's our 48th anniversary.

Marv J
 
I agree with Marv. never seen those type bleeders, but have heard of them.
I have found that the Healey brake system can be a bear to bleed. i should say at least for the disc brake cars like mine. I personally believe it is because the square area of the master cylinder is too small for the area of the calipers. the plunger in the master does not move enough fluid to get much effect from one stroke of the pedal. when doing it the old fashion way. When the system is fully bled, it works fine because you don't have to displace much fluid to apply brakes. But when the system is full of air, the full stroke of the piston doesn't move enough volume to push much air out with each stroke. So either use some more sophisticated method, or use perserverance and pump alot.
 
Mike -

Those bleeders are modern aftermarket bleeders meant to make bleeding easier (for most cars) if you pump the pedal.

The problem is they really won't work very well on a BN1's front brakes as the bleeder screw is NOT at the very top of the slave cylinder. This means that if you pump the pedal, it makes it very hard for all the bubbles to come out of the system, and out the aftermarket bleed screw.

You do have the procedure right - the Ezibleed kits are the best option you have to bleed out the air on a BN1 - the only problem are these ball valve bleeders you have. Either get rid of the balls or replace the bleed screws with off the shelf bleed screws and your problem will be solved.
 
Oh good, one of my next jobs is to bleed my brakes (BN1 front BN2 rear) sounds like i'm in for some fun and will need to schedule a full day.

I'm not sure abut these being after market bleeding screws. I have read somewhere that early cars had this arrangement and more importantly have come across them on some A90 spares that came with my car. If they are a problem i don't see any reason not to replace them with the more common bleed screws.

Dougal
 
Dougal said:
have come across them on some A90 spares that came with my car.

Dougal
Click to expand...

Well, I know it's across the straight to Wellington .... That's where I bought my A90 (from Roy @ McGuinness Classics)

Yet... some of those parts might actually be off My car!

060911%20A90%20side.jpg


By the way, am now driving the A90 thrice weekly to work in HK. Good fun and the ladies love it (don't tell my wife!).
 
Its your call, but you could give bleeding the fronts by pumping the pedal quickly to force as much air out as possible before the bubbles can migrate away form exit (all you are out is a little brake fluid) and if it doesn't work get regular bleeders (cheap enough and should be readily available) and use your EZ-bleed.

I purchased the speed bleeders or whatever they are called for my MGB, which has rear wheel cylinders with the bleeder low on the cylinder instead of high (making it hard to get the bubble out like the BN1) and with some work and spilled brake fluid they did the trick.

With the valved bleeders there are still some tricks to get them to work the best--one trick is to use teflon tape or anti seize on the threads so they won't suck air back in through the threads when loosened for bleeding.

One thing I found with my BN1, in addition to bleeding the brakes, mine were very sensitive to the handbrake adjustment, I was pulling my hair out with an issue of the right rear locking up prematurely on brake application, finally fixed when I got underneath the car and tightened up the emergency brake adjustment, don't know why this made a difference, but it did. This after new shoes, two used drums swapped out, getting said drums turned and much brake adjustment and fiddling.
 
Alan, if you want your brake cylinders back just let me know....ha ha. Oh and FYI McGuinness Classics must have hoped over the ditch as they are now in Sunny Christchurch.
 
Tell Roy at McGuinness he owes me at least 3 pints, I bent a push rod on the motor only 100 miles after taking delivery - ended up rebuilding the whole block!
 
healeynut
As an aside, I might have found a source for repo plastic VIN plates as found on the early BN1's
 
Hey all,
Thanks for the advice and info. I might have been inaccurate in explaining
the ball bearing issue. This ball bearing is inserted in front of the bleeder
screw and of course falls out and rolls under the car and as far away as
humanly possible from you when you take the bleeder off. The 100-4 series
repair manual I have clearly shows the ball bearing installed in front of the
bleeder screw as being a stock type deal. Regardless, think everyone knew
what I was talking about and seems all agree to leave it out. I am going to
double check but seemed when I did leave it out that I could tighten up the
bleeder screw so no fluid leaked out as without the ball bearing need to
make up about 1/8 inch more depth. I'll let everyone know what I come up
with after I go back and tackle the problem.
Thanks,
Mike
 
zblu said:
healeynut
As an aside, I might have found a source for repo plastic VIN plates as found on the early BN1's
Click to expand...

Cool, let me know how it goes. I will probably want to order 3 (I need them for my A90 also)
 
bighealeysource said:
Hey all,
The 100-4 series
repair manual I have clearly shows the ball bearing installed in front of the
bleeder screw as being a stock type deal. Regardless, think everyone knew
what I was talking about and seems all agree to leave it out.
Click to expand...

Good to hear Mike. I think the problem with the ball in there is with surface tension it tends to keep the bubbles from escaping, unless the bleed screw is at the top where there's enough force from the bubble to overcome the surface tension. I think that's the issue with this.
 
Ah......bleeding the brakes. What memories this brings back!
I have seen the bleed nipple with the ball-bearing and have even been advised that my car should have them.
For years I thought the only way to get a "pedal" was by pressure bleeding (from the master cylinder).
When I finally restored my 100, I replaced all the brake lines including the flexible hoses. I was dreading the day when I needed to ask my wife to help by operating the pedal. When the day finally arrived, we had the job done in a few minutes!!
I thought "that can't be right" so we did it again, and again.
Sure enough, the brakes were great and have stayed great.
Moral: Make sure the system is clean and without obstructions.
 
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