Alfa Romeo Forums banner

1 - 6 of 6 Posts

·
Registered
Joined
·
1,463 Posts
Discussion Starter #1
I replaced my master cylinder when the pedal went flat and although that helped, it's still not right. I'm having a couple of problems. First of all, the car pulls considerably to the right. Is that always a caliper issue and can I check it? And is it always a front caliper issue? And what usually goes bad with these calipers?

Next, when braking hard, the engine races. I've noticed that there is no valve between the brake booster and the engine in the hose. Should there be a valve and is this the cause of the revving? And if there is no valve, would this cause other problems with idle or Spica ?
 

·
Registered
Joined
·
317 Posts
First off, block the vacuum port on the motor and see if your symptoms change. A ruptured diaphragm or seal would cause a vacuum leak and change the idle speed. There is only a check valve and this is one way toward the engine so it would not prevent an air leak if the booster failed.

If you replaced the master cylinder, the whole system should have been bled. Try bleeding it again. If it doesn't improve, a caliper can 'stick' and a brake flex line can fail internally, seemingly acting like a stuck caliper. After driving a bit to warm up the brakes, check the temperature of the rotors and see if there is a noticeable difference, the hotter side is 'stuck'. The calipers can fail 'stuck' or leaking and both are correctable with new seals, unless there is severe corrosion due to moisture internally.
 

·
Registered
Joined
·
1,463 Posts
Discussion Starter #3
First off, block the vacuum port on the motor and see if your symptoms change. A ruptured diaphragm or seal would cause a vacuum leak and change the idle speed. There is only a check valve and this is one way toward the engine so it would not prevent an air leak if the booster failed.

If you replaced the master cylinder, the whole system should have been bled. Try bleeding it again. If it doesn't improve, a caliper can 'stick' and a brake flex line can fail internally, seemingly acting like a stuck caliper. After driving a bit to warm up the brakes, check the temperature of the rotors and see if there is a noticeable difference, the hotter side is 'stuck'. The calipers can fail 'stuck' or leaking and both are correctable with new seals, unless there is severe corrosion due to moisture internally.
Thanks for the tips. My car is missing the check valve so I'll try and track one of those down. System was bled but I'll try it again.
I hope it's not the booster as these are always an expensive part. Hmmm, wonder what manual brakes feel like.....I guess I'll try disconnecting the vacuum as you suggest and see what happens.

More to come.....
 

·
Registered
Joined
·
1,463 Posts
Discussion Starter #4
Ok, it's not missing the check valve, it has a valve in the hose and then also a silver metal one on the head where the hose connects. Which one is OEM? I don't think there is any problem with the booster. Brakes seem a bit better but now they pull quite strongly to the right under hard braking; is that always a front caliper issue or can the rears cause pulling to one side also? Also, front end alignment is way off so it could also be that. And do the rebuild kits work or is it better to replace with a rebuilt or new caliper?

And finally the revving when braking: I think this could be because the engine tilts forward under braking, stretching the accelerator cable. I have new motor mounts to try and firm things up. The accelerator cable is stretched at all times. I have a Shankle heel and toe kit on the cable which only makes it worse but I do like the kit. Not sure if the cable bracket is bent or if the motor mounts have sagged and stretched the cable but something is going on....
 

·
Registered
Joined
·
112 Posts
when you are sure the system is bled correctly....

did you have the pulling to one side problem before the pedal went flat?

I did get a new brake booster etc, but also had to renew the brakehoses to make it brake straight again!
I used black goodridge hoses. My sedan still had the original 1982 hoses!
 

·
Richard Jemison
Joined
·
7,079 Posts
Brakes

Look at the repair manual for ATE brakes.

First be sure the piston`s milled section`s edge is positioned correctly relative to the side of the rotor and rotor direction.
Simply the flat edge should face the rotor`s in-comming angle at 90 degrees to rotor movement at the piston`s position.
Other wise pistons can clock at an angle, bind the brakes and cause tapered pad wear as well.

I suggest you open the bleeder screw and fully retract the pistons to the bottom/end of their bores.
Then replace the pads with new ones, pump up the brakes, bleed again and the problem will likely be solved.

You should only have the vacuum valve that fits into the #4 intake runner. Pull it out and if you can force air outwards from the port end replace it.

However with an Alfetta, you have a Marelli distributor which notoriously have weak return springs on the advance mechanism and don`t return the ignition to it`s un-advanced position. This causes both high idle and or very slow return to idle.
 
1 - 6 of 6 Posts
Top