Dull Brakes - 79 GTV

[joestram]

Hi All,
I have an issue what is kind of annoying me.
It seems as thought my brakes don't seem very responsive. The car has had a new master and booster put I it just a few month ago so I was hoping that the brake would have improved but they haven't.
Does anyone have any ideas as to what else it could possibly be?
Is there a way to adjust the brake power I these things?
Thanks in advance.
Joe

[Cool Jesus]

Brake bias is factory set. It's a valve that is either in the master cylinder or a little unit that sits under the car below the left rear seat I think. I don't believe that's what your after though.
How old are the flexible brake lines? They could be taking some pressure away and swelling, I've read about owners installing the stainless braided lines to remove that flex.  It would certainly help in keeping pressure to the pads.
Another issue is adjusting the rear brakes, they can be fiddly.
Your discs may be glazed if new pads weren't bedded in properly?
One final possibility is air in the lines, try bleeding the brakes again and don't forget the clutch line?
From what your describing though I'd look at the flex brake lines.

[Cool Jesus]

Just had another thought, are confident the brake servo is ok? Sorry just realised this is what you meant by booster. In that case, make sure there's no air leaks in the line and the valve is working at the manifold.
I guess it comes down to where you're feeling the abnormality, is it in the pedal or at the wheels?
Spongy pedal would definitely indicate air in the system. Having to push hard would indicate a booster issue.
Brake fade would be glazed discs or lose of pressure due to cylinder seals or old flex lines.
Just a few points that come to mind if you can't be more specific on the dull brake symptoms.
I stand to be corrected, but the set up was adequate for this model, so you shouldn't feel a lack of responsiveness. Unless you drove it hard, at worst you'd get some fade from heat.
Keep in mind that the rear discs aren't self adjusting, hence adjustment is a regular service requirement.
Responsiveness? Yeah I'm leaning towards glazed discs or lose of line pressure per advice above.

[festy]

Old rubber brake hoses can expand a fair bit under pressure, which increases the hose volume so decreases line pressure to the pistons.
Goodridge make an ADR approved braided hose kit for the Alfetta GTV (# SAR0100-3P) that's really not much more expensive than standard rubber hoses, and being teflon lined they'll outlast the car.

Have you checked that the booster is securely mounted? Get someone to stomp on the brake pedal while you see how much the booster moves - you'll see the firewall flex a fair bit but make sure the bracket isn't moving around or anything.

Are your calipers in decent condition? I'm just finishing off rebuilding mine today, and was surprised to find that 3 of the 4 were more or less siezed - yet it was still somehow managing to stop reasonably well.

Have you flushed the brake fluid recently?

[hammer]

It's amazing the difference rebuilding your calipers makes. We always replace pads, skim rotors, replace fluid and bleed brakes but rarely thing about the condition of the calipers.

I recently had the front calipers on my Giulietta race car professionally rebuild and was astounded by the difference in brake performance.

Cheers,

Brent

[Cool Jesus]

How much are we looking at to rebuild calipers?
Have been toying with the idea for my Alfetta project.

[festy]

If you're doing it yourself, roughly $70 for the kits.
They're pretty easy to rebuild, the rears are a little more complicated than the fronts due to the handbrake and adjusters - but even they are easy enough.

[hammer]

$380 to have my fronts done professionally. They're a 4 piston alloy caliper.

That's not just putting a new seal kit in them though, it's honing the bores, painting the calipers, installing new bleed nipples and installing the seal kit. I could only have done half the job if I'd done it at home.

Cheers,

Brent

[Cool Jesus]

Well thats not too offensive for a pair of fronts. Will keep it in mind if the bores are stuffed.

[festy]

The OE Alfetta ATE calipers have the seals in the bores (not on the pistons) so honing isn't required because the bore isn't a sealing surface. 
The pistons are stainless, so a quick polish on a buffing wheel is all they need.

[Cool Jesus]

That's even easier, I'll. just freshen then up with a kit myself then.
How about you joe, any luck on your brakes?

[joestram]

WOW - thanks for all the replies and information guys!

I will try and get myself some new lines and see how that goes first.

Is it safe to drive around with the rubber hoses if they expand? Its not like they are going to burst are they?

The car has just passed a RWC as well so I am assuming the discs and pads are still in good shape.

When I press the brake pedal and the engine is off, I do hear a clunking noise (not sure if that is normal) coming from the booster/master area.

The brakes also have nice bite when the car is rolling very slowly so this might also indicate the lines need to be changed?

Thanks

Joe

[festy]

AFAIK all rubber brake hoses expand to some degree even when new, but they get a bit more elastic as they age. It's not always a sign of impending failure.
Braided teflon hoses give a better 'feel' because they don't expand anywhere near as much, so more of the pressure goes to the pistons.
Rubber hoses have a finite life. For aviation use, even braided rubber hoses need to be marked with an expiry date whereas teflon hose apparently lasts forever and doesn't expire.
My Goodridge hose kit (2 fronts and 1 rear hose) cost about $80 from a UK ebay shop, whereas I'd expect a set of rubber hoses to be >$60 anyway.

Have a close look at both ends of your hoses for cracks. This one doesn't leak (yet), but I wouldn't be too keen to rely on it 
You could probably feel this hose expanding if you held on to it while the brakes were applied.

[Cool Jesus]

There shouldn't be any clunky noises joe. Try and pinpoint the source, my bet is the booster as has been mentioned above. Check for movement and flex in joints and anchorage.  Perhaps it wasn't installed properly and your getting no boost, although you'd find the pedal very hard the push down?
IMO the braided brake lines are a worth while upgrade, if not a must.
Make sure you follow up the thread with result on the fix.

[joestram]

Hi All,

I took it for her out for a short drive yesterday, but before I did, I checked the brake lines. They look like brand new rubber hoses which as you all suggested, might be swelling.

I will make sure I go out and get some braided ones and update you all on the differences (if any).

Thanks

Joe