Alfetta brake advice needed

[hammer]

G'day,

Need some advice on trouble-shooting troublesome Alfetta brakes.

Bought a well used Alfetta sedan track car last year for my brother to use and have been having ongoing problems with the brakes. The original owner warned that the pedal was feeling a bit spongey but thought it probably just needed a good bleed or perhaps new fluid. He had raced it about three months prior to us taking delivery of it.

Upon further inspection it appeared the rear calipers both had leaks, so we whipped them off and had a very credible Alfa mechanic rebuild them. When refitted, however, we couldn't get any decent pedal, no matter how much we bled the damned things. Tried driving it for several laps around the Lakeside service road to bed in the rear calipers, then re-bled the system, but still a soft, ineffective pedal.

We pulled a very good master cylinder off a Gulietta that had been crashed a few weeks before (kindly donated by Rob Robson), but the ensuing bleeding process resulted in just as shitty a result.

We figured that this second master cylinder must also be stuffed, so had the original one completely rebuild by a brake & clutch specialist. Today we fitted the rebuilt master cylinder, bled the bejesus out of it and it still feels like a sponge.

Could this be a vacuum booster issue, or should we still be able to get a good solid pedal if everything in the hydraulic system is working efficiently?

Any tips would be greatly appreciated. Otherwise we'll just have to load it onto a trailer and take it to a brake shop.

Cheers,

Brent

[dehne]

how are all the hoses maybe 1 has a pin prick leak in it,

[hammer]

Choder,

No apparent leaks that I can find.

We are just doing the old two man pump through bleed, starting at the right rear and finishing at the left front. I might be best to take it somewhere to have a pressure bleed done.

Cheers,

Brent

[bt46]

I think I have posted this before so ill make it brief.
Bleed the rear calipers both nippels open at a time.
Use a air pressure bleeding device if you can they are fantastic.
Remove earth lead on batt and jam brake peddel down over night with a steering lock or piece of wood. Sounds stupid but gives you a rock hard peddel if all is well.

[Darryl]

I don't know the secret, and neither did the brake mob I it to - came back soft with a - breaks are bad/maybe it needs the brakes rebuilt excuse... But I'm more persistent than they are - flushed through with a lot of cheap fluid, bled normally, bled some more.. Did the pedal down overnight trick, bled some more, got a decent feel, and *very carefully and slowly* "pumped" the good stuff through and ended up with a good pedal. If I'd been charging myself labour it would have been a very expensive job.

Are the hoses new - maybe they are soft even if not leaking? If they are old it might be less "exciting" to replace them now just to be sure?

Don't give up!

[aggie57]

Over the years we've had success fixing this by raising the rear of the car so that the rear calipers are higher than the master cylinder.  Same theory as choderboy's reverse bleed I guess.  Whatever the reason, worked everytime. 

Alister

[hammer]

Thanks boys, many tricks to try.

I like Darryl's Churchillian advice "never give up".

Cheers,

Brent

[Mike]

In my experience, I have NEVER got a good pedal whether with pressure bleed or 2man bleed when trying to bleed furthest to closest as per the crap Haines manual and every other car on the planet.  I don't follow the hold pedal down and let rear callipers bleed theory (but hey if it works!).  I do however subscribe to making up a cap to fit over the master cyl reservour  and vaccum bleeding (like Chowder says, air rises).  An alternate to having to be tortured by this every time is fitting a high point bleed, I'm sure if you study the lines you'll spot where the air gets trapped...

I also have taken brakes to Alfa 'specialists' only to have the brakes come back just as bad.

I like the arse of car in air option....must be pretty high though!!

[MD]

Hammer,some more pointers that work for me:

Check all rubber hose under pressure for small bulbs forming about the size of peas. This can happen on brand new hoses too!
low likelihood.
Keep in mind the Alfetta brakes via the booster will ALWAYS have a shitty pedal and never a rock  hard one. The firewall flexes and so does the tranverse bar assembly giving the weird pedal feel whilst the car is not under power. The actual operation of the brakes may be a lot better than it feels stationary and this is the usual story.
Best move is to get rid of the booster and fit new lines to a modified pedal box. Brace firewall where pedal box is mounted.

Now for the bleeding.

I start at the front with the caliper closest to the MC then move to the next one. Finally I bleed the rear brakes at the same time.I use a vacuum bleeder because pumping the brake pedal will cause the air molecules to be incorated into the fluid so that cumulatively you still have air in the lines. Vacuum bleeders do not create this problem.
Finally (if necessary)(as others have said) pressure bleed the MC itself after allowing the car to sit for a day /overnight.

Resting the fluid overnight allows the air globules to aggregate into larger clumps which can be removed more readily. So the first thing in the morning is a fresh bleed all round.

I am very happy to lend you my workshop vacuum bleeder if you decide to go down that track or have problems in the future. You need a compressor.Give me a call at home if you need more help.

[alfa duk]

Seems everyone has had this trouble and i am no different. There is a point in the brake line where the air gets trapped and is very difficult to remove. The arse in the air method was the one that fixed it for me, at least enough to give me confidence in stopping then after each supersprinting session, bleed em again. I think i did it 3 more times to get good pedal. Doug

[hammer]

Thanks all. MD, I'll most likely give you a buzz on the weekend about that vacuum bleeder. Will also trailer the car over to my place, so we can put it on a nice flat concrete floor, in my garage, in the shade. We were partly in the sun on Sunday, which was a stinking hot, humid Queensland Summer's day. Combine that with inboard rear calipers, large gorilla hands, soft-cock pedal, flies, and Chris's bull terrier trying to lick me every time I lay under the car and it's no wonder we couldn't get no satisfaction! (credit Jagger/Richards).

[bt46]

Its funny how experiences differ.
I have always had a good hard pedal on my alfettas even if the brakes havnt been that effective (usually locking a front wheel to early).
Need to add that you make sure the rear calipers are adjusted correctly otherwise you will have alot of pedal travel. Pull the handbrake on and see if the pedal feel improves as this can indicate incorrect adjustment.
Mike I cant agree that the hanes manual is crap. I thinks its a very good manual for someone learning to follow.
To be clear im not suggesting you open the rear nipples and hold the brake pedal down. After bleeding the system jam the pedal down over night. The master cylinder is the highest point.

[aggie57]

Actually I'm the same as bt46 - getting a decent brake pedal is perfectly possible on an Alfetta even with the cross-bar setup on RHD cars.  As he says making sure the rear calipers are adjusted correctly and that the self adjusting mechanism works correctly is part of the answer (in my humble experience) as is making sure none of the pads are tapered, overheated or plain stuffed.

Alister

[Martyn]

Hammer
Its a track car. Get rid of the servo cross bar save yourself 10kg!Mount existing master cylinder right on pedal box. One bracket and a bit of thought.
Look at my engine bay pic where my Alfetta GTV Sc is for sale on Buy/Swap/Sell forum (6 Feb 11)
I agree with some of the other advice that old flexible brake lines can puff up enough to loose the hydraulic pressure. Put a
set of vice grips on rear flex line at back of transaxle.If pedal is hard then bingo! Get new rear flex lines.
Regards
Martyn