[Healeys] BN2 Brake Problem

[john harper]

Bob

I suggest that you look for a fluid leak. I had one from a relatively new
wheel cylinder where there was a leak where the pipe bolted in. I suspect
that it was a flaw in the original material. As the leak was inside a drum
I did not see it originally.

Another possibility is that the master cylinder piston is no coming back
enough. It is important to adjust so there is about 5/8" pedal slack. If
there is no slack this can cause problems but this is usually that the
brakes come on by themselves and get worse as the shoes warm up.

On Sun, 25 Apr 2021 at 02:45, Bob Spidell <bspidell at comcast.net> wrote:

> (non) progress report:
>
> Thinking Bill probably had the explanation, I clamped off the RF flex
> line--the wheel I'd replaced the cylinder on--per Michael's suggestion and,
> Voila!, a nice hard pedal. Thinking also that I hadn't expelled a bubble,
> like Bill also suggested, I increased the pressure on my pressure bleeding
> rig and bled all wheels again. Still, a nice hard pedal, so I fired up my
> BJ8 to get it out of the garage so I could pressure wash the undercarriage
> of the BN2 and take it (BJ8) for a warm-up spin. Halfway around the
> 'block,' about 5 miles from home it started running very rough so I pulled
> into a covid-closed restaurant parking lot and popped the bonnet; coolant
> all over the passenger side of the engine bay. It appears the gasket under
> the brass shut-off valve for the heater hoses sprung a leak, so a call to
> AAA was in order. After getting the BJ8 flat-bedded home I washed the 100's
> underside, put on the new wheels and tires and hop in ... brake pedal goes
> to the floor! Since I could get some brakes if I pumped the pedal a couple
> times I took a chance on a short, abridged spin around a smaller block--the
> new wheels and tires ride fantastic, and no 'scuttle shake' detected--then
> parked it.
>
> Thanks for all the suggestions, folks. I meant to try the
> 'hold-the-pedal-to-the-floor-with-a-board' technique, but by EOD I was so
> beat I forgot. I've had trouble bleeding brakes on the BJ8, but the BN2 has
> generally cooperated until now. Damned if I can explain why I can get a
> good hard pedal, which proceeds to go soft from just sitting. Good thing I
> love these cars.
>
> Bob
>
> On 4/23/2021 9:06 PM, WILLIAM B LAWRENCE wrote:
>
> The problem with the double leading edge brakes on the 100s and 100-6s is
> that the bleeder screw is at a low point in the system so it takes a little
> extra effort expel any entrained air. You probably got a pretty good slug
> when you changed the wheel cylinder. Probably keep bleeding that wheel and
> use various techniques until you find the one that actually moves the air
> out of the bleeder.
>
> Bill Lawrence
> BN1 #554
> ------------------------------
> *From:* Healeys <healeys-bounces at autox.team.net>
> <healeys-bounces at autox.team.net> on behalf of Bob Spidell via Healeys
> <healeys at autox.team.net> <healeys at autox.team.net>
> *Sent:* Saturday, April 24, 2021 3:04 AM
> *To:* Healeys <healeys at autox.team.net> <healeys at autox.team.net>
> *Subject:* [Healeys] BN2 Brake Problem
>
> Listers,
>
> I have a problem with my BN2's brakes that is driving (heh) me up the
> wall. Here's what I've done:
>
> - new shoes and cylinders in both rear wheels
> - one new cylinder in one front wheel (there's a total of 4 in the 2
> front wheels)
> - new master cylinder
>
> I hadn't touched the M/C, so after all the installs I just pressure bled
> as I usually do (this has worked well on my BJ8 for decades and a couple
> times for the BN2). At first, I got decent pedal then, after a period of
> time I lost it; the pedal would go to the floor with only slight
> pressure (probably from the return springs). Thinking it could only be
> the M/C, I sprung for a new TRW brand M/C but after installing it and
> bleeding I got the same results. I've put 2 full quarts of Castrol's
> finest 'synthetic' DoT4 through the system and tried vacuum bleeding and
> old-fashioned 'pump and hold' method; same result for all methods. I'm
> not losing fluid as far as I can tell, and the pedal will pump up a bit
> with a half-dozen or so strokes, but will go back to the floor after
> some time.
>
> Any and all ideas and suggestions accepted and welcomed.
>
> TIA,
> Bob
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>
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