terry gt

IMHO the oem lines would be steel and the color is from a coating . SS works as well just a little harder to work with

BC

It was galvanized steel, but I see your point. That site has some nice stuff. I guess in that case you would just tap into the rear line and go from euro to AN to get in and AN to euro to get out.

atb

So I got my Wilwood proportioning valve in the mail today.



If all goes as planned, I hope to receive my new clutch master by the end of the week.

I imagine by Sunday I'll be a bubble flarin' fool trying to get all these new hydraulics installed.

I was initially planning on just ordering a stock of brake line, fittings, and making my own. But a quick trip to the local independent parts store shows that they have pre-made brake lines - fliared with fittings - on the wall. Just choose your length and bend to fit. My plan is to use these as much as possible, and just fabricate where I need to. We also have a great local hydraulic hose shop, so I may see what pricing they have for special lengths before I make this a total DIY.

Quick question. The Wilwood bias valve says its good from 1000 psi to 100 psi. I'm presuming that means at full open (actually, with the **** cranked all the way down), the max pressure that the valve will allow to flow is 1000 psi. Does anyone know the line pressure of the S4 brake system? I'm trying to determine what the range of adjustability is going to be once I install this, if it will be truly be 100 to 1000 psi or something less.

FBIII

Do you have to run the S4 hubs on an OB conversion when you do the full front suspension conversion? Or can you run the OB hubs without the abs ring?

The Forgotten On

If it's an OB you need to change to steel lower ball joints, 993 front rotors (ironically cheaper than S4 fronts), and caliper adapters with S4 caliper bolts, and appropriate brake lines. This applies if you are keeping with OB front suspension. There really is no need to change to S4 suspension especially since some of the parts are not serviceable and it is a pain to install. And yes you do keep the OB front hubs.

atb

^^^^^
The exact set up I'm running on this car.

FBIII

You didn't answer my question. I'm running the full S4 suspension as I stated in my question. I prefer this setup because I already have these pieces and I prefer the shorter suspension arms making wheel backspacing a little less critical. I have also heard of issues with spacing between the ball joint and rotors when using the adapter setup.

I would still like to know if I can use the OB hubs with my S4 control arms and upright.

atb

Here's the rough in installation. Took a some practice, but finally got the hang of making bubble flares. Nothing is anchored down yet, but this is pretty much the final install.

Props to anyone who has replaced a booster without removing the engine, seems like it would be impossible.

I retained the stock lines wherever possible. They are much softer than steel, and are no problem to flair on the car. The steel ones I did on the bench in the vice to be able to hold them dead square.



Now I need to turn to the pedal side of things and finish up. Need to install the brake light switch and see what's going on with the linkage, it looks too short to reach the pedal at the moment.

Lizard928

Ok, factory is 18 bar so 261 psi
33 bar is 478

I would start at around 500 with your suspension setup and increase from there

To set, wilwood has a pressure gauge which threads into the caliper instead of the bleeder and reads the pressure. So install have a helper push the brakes, then watch the pressure and adjust. The helper has to hold the brakes at max pressure for this to work.

atb

Here's the final install. Hope it doesn't leak .
The adjustable bias valve has ten turns of adjustment and max's out at 1000 psi, so I've got it set to 5 turns out which hopefully equates to 500 psi. Guess I'll have to see what the pressure gauge has to say.

Looking forward to having awesome pedal feel that the OB 9" booster and criss cross master cylinder biasing just wasn't delivering with the S4 calipers that I've been running for awhile.

atb

So, the 9" booster has a longer shaft than the S4 10" booster, requiring a different (longer) piece of brake linkage. See below:

hacker-pschorr

That's interesting. My 79 still has the stock booster. I've debated going to the later one but wasn't really interested in what it would take to make it fit. I haven't really looked into it though......

It depends on how you do it.

My 79 still has the OB upper and lower arms, spindle and hub with S4 calipers and standard S4 rotors.

The spindle is modified (no brackets), and they fit under 16" phone dials.

atb

The last piece of this upgrade is wiring the brake light switch. The stock OB master cylinder has two pressure activated switches on it to activate the brake lights. Pictured below is the S4 set up. You can see the plunger switch is mounted on an "L" bracket in the footwell. The OB does not have bracket, so I'll need to fabricate something.

atb

How's your pedal feel been Erik running the stock booster? I had very little pedal feel running the S4 calipers with the stock OB hydraulics. I'm really hoping this project gives me what I'm looking for.

hacker-pschorr

The upgrade was done 20+ years ago long before I owned the car. Feels fine to me, no issues on the track.

I've only driven it with Pagid Orange pads and SuperBlue fluid.

It would be kind of funny if the booster was already upgraded. I don't remember the builder of my car mentioning that and I still talk to him on a regular basis. I'll have to measure it and see.