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Discussion Starter #1
Hi All,

I replaced the front rotors which means I disconnected the front brake lines. Do I need to bleed all 4 brakes or just the front ones?

As I understand it, the front brakes have dedicated lines so I can bleed them in any order and the rear brakes have their own line so there's no need to bleed them in this case. I've never bled brakes before, let alone on my Spider, so any and all tips are welcome (I'm using a MityVac if that helps).

Thanks,

Hector
 

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You should only need to bleed the fronts. But it wouldn't hurt to bleed the rears, too - that will help push some fresh fluid through the whole system. Brake fluid is hygroscopic - it absorbs water. It is advised to flush brake systems every 2-3 years for that reason.

When bleeding a system that has been in use for a few years (vs a brand new master cylinder) I will put a 2X4 piece of wood against the toe board so that the pedal won't go all the way to the floor. This avoids having the master cylinder's seals sweep over sections of the bore that hasn't been touch in years. There might be some roughness or debris that could damage the seal's knife edge. The downside is it takes more pedal strokes to move enough fluid to bleed the system. I've never used a MityVac so that might not be an issue for you.

Advice - apply a few drops of penetrating oil to the brake bleeder's threads a few hours before you try to loosen them. Then use a six point socket to break them loose. This helps avoid breaking the bleed screw or rounding over the flats. And no need to over-tighten them when you're done. Snug with a short wrench to avoid too much torque.
 

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Eric has said it all really but just to add; I used a Gunson pressure bleeder which worked really well.
It connects up to the spare wheel, reduced to 20 psi, and pushes fluid from a separate reservoir. It made life easy - no need to push on the brake pedal.

I would second the idea of doing the rears as well, even though you are correct about the circuit for the S4. You might as well change all the fluid while you are down there and it doesn't take long.
 

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Discussion Starter #4
Thanks guys for confirming and the tips - good point about the overall bleeding since I'm already there.

I got lucky on loosening the bleeders since I didn't use the penetrating oil, but will keep this in mind for the future since I probably used quite a bit of force and it could've gone wrong for me.

The Gunson bleeder looks like a great way to go...I don't think I can return the MityVac at this point w/o paying shipping so I'll stick with that.
 

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I have a Mityvac and it works great. I was about to make a pressure bleeder before getting the Mityvac as a gift. I have a 1 gallon sprayer and all the stuff to make one for less than $30.

1 question though, since when I had my spider it had brand new pads and rotors so I never touched them. Can't you just remove the calipers and hang them up to replace the rotors? You must remove the hose from caliper?
 

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I bleed all of the brake and clutch hydraulic lines on all my cars every other year. It's good insurance against corrosion in the piston.

I used to do the old two-person pump-up-method until my wife started complaining.

Used a vacuum bleeder for some time (Sears brass one, not a Mighty-vac but the same thing basically), but found that it often sucked air past the threads of the bleeder valve, particularly if the threads were slightly worn. If that happens, one solution is to wrap pipe tape on the treads (OK for brake fluid, not for anything else on a car), but taking the bleeder valve all the way out is messy and a pain.

Finally bought a Motive pressure bleeder and a fitting for European cars (fits all of the brake and clutch reservoirs on my Volvo, Mercedes and the Alfa). Best method by far to bleed hydraulic lines although it is somewhat wasteful of fluid since I dump what's left in the bottle.

Some cars may have been converted from DOT 3 or 4 to DOT 5 since it is not hygroscopic, but they don't mix so make sure you know what's in the system. Changing over requires a full system flush and frankly, I don't recommend DOT 5. DOT 3 and 4 can be mixed but the Alfa specifies DOT 4 as you probably know.
 

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Discussion Starter #7
AlfaTango: On my S4 the lines to the calipers are metal so they had to be disconnected. The manual seems to indicate the same so I guess this is typical for S4s. Its a pain they would be like this, but maybe there is some method in the madness (like forcing you to flush out the fluid every now and then?).

Richard, do you use the yellow pipe tape or white - does it matter? I'm thinking I'll just put the tape on the bleeder screws now while its all dry and non-messy.

I don't think I have DOT 5, is there any way to know for sure?
 

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Used a vacuum bleeder for some time (Sears brass one, not a Mighty-vac but the same thing basically), but found that it often sucked air past the threads of the bleeder valve, particularly if the threads were slightly worn. If that happens, one solution is to wrap pipe tape on the treads (OK for brake fluid, not for anything else on a car), but taking the bleeder valve all the way out is messy and a pain.

Finally bought a Motive pressure bleeder and a fitting for European cars (fits all of the brake and clutch reservoirs on my Volvo, Mercedes and the Alfa). Best method by far to bleed hydraulic lines although it is somewhat wasteful of fluid since I dump what's left in the bottle.
If you have any air being sucked at bleeder where hose connects or on threads grease works good too. I just slop a bit all around and it usually work real well.

Here's a pic of the pressure bleeder I'm sure I'll build sometime in the next few months. $15 sprayer, $6 gauge, $3 pvc cap (the one in this picture is made for the job obviously) and some hose.
 

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AlfaTango: On my S4 the lines to the calipers are metal so they had to be disconnected. The manual seems to indicate the same so I guess this is typical for S4s. Its a pain they would be like this, but maybe there is some method in the madness (like forcing you to flush out the fluid every now and then?).

Richard, do you use the yellow pipe tape or white - does it matter? I'm thinking I'll just put the tape on the bleeder screws now while its all dry and non-messy.

I don't think I have DOT 5, is there any way to know for sure?
Ah, I see. :)
 

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I don't think I have DOT 5, is there any way to know for sure?
The DOT 5 (silicone) that I have seen has been tinted purple. But there is a DOT 4 brake fluid that has been tinted blue so that may not be a perfect way to tell the difference.

And, to confuse us, there is a DOT 5.1 brake fluid that is NOT silicone.

Now if our pal Tifosi (RIP) was still around he could probably tell us how to tell the difference by tasting them...!
 

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Discussion Starter #11
Thanks Eric...the fluid is a clear color so I think I'm ok on using Dot 4.

The grease on the fitting seems like a good idea, but is there a risk of contamination? If so, would it be ok to use caliper grease? What do you use?
 

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AlfaTango: On my S4 the lines to the calipers are metal so they had to be disconnected. The manual seems to indicate the same so I guess this is typical for S4s. Its a pain they would be like this, but maybe there is some method in the madness (like forcing you to flush out the fluid every now and then?).

Richard, do you use the yellow pipe tape or white - does it matter? I'm thinking I'll just put the tape on the bleeder screws now while its all dry and non-messy.

I don't think I have DOT 5, is there any way to know for sure?
I have an S4 too. Yes, the metal connectors have to be disconnected to remove the calipers but with routine bleeding it doesn't.

As I recall, I used to use at least two wraps of white tape, one of the thicker yellow gas line tape.

DOT 5 smells different. DOT 5 is uncommon but I run into some old cars (even very old) at the museum that don't get serviced very often where the owners have converted the brake fluid to DOT 5 because it won't absorb water from the air when it is sitting for long periods.
 
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