924Board.org

BionicBalls · Joined: 05 Jan 2009 Posts: 642 Location: Charlotte, NC

I'm about to do my 5 lug swap. The only question I have is regarding the master cylinder from the 944. I have read that The 924 has an X setup and the 944 has a TT setup. What do I need to do to make the 944 MC work? Do I need to swap out hard lines/reroute them? I'm a little unclear about this part of it. Everything else seems pretty straight forward.

Also, is it necessary to change out the spindles from the 944 to my 924? It looks like I just need the hub, rotor, and caliper from the 944.
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1980 924 NA
1982 931

Rich H · Posted: Wed Apr 07, 2010 4:58 pm Post subject:

Yes you need to change the pipework to H pattern.
Yes you need to change the spindles.

IIRC the MC from 944s is stepped so the rears get proportionately less braking force. It's not hard to replace the pipes but it takes time and needs doing. I used Kunifer pipe and did it in an afternoon, I brought the rear brakes together at a 'T' by the torsion bar carrier and the fronts have a port each.

The 944 inner wheel bearings are different sizes (Larger) than the 924. You will need an alignment check after changing the spindles.

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1994 Lotus Esprit S4 - Work in progress...
1980 Porsche 924 S2 DITC Turbo - Original spec
1978 Homo-Sapiens - Tired spec
1953 Landrover S1 - Pensioner Spec

924RACR · Posted: Wed Apr 07, 2010 9:43 pm Post subject:

IIRC the booster is also bigger, for the 5-lug setup.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

morghen · Joined: 21 Jan 2005 Posts: 9095 Location: Romania

i didnt change the brake lines from X to H...dont know if its good or not..but i think i'm going to try to change to H to see if there is any difference.
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Supercharger and EFI kits
https://www.the924.com

Rich H · Posted: Wed Apr 07, 2010 9:52 pm Post subject:

IIRC that the 924 Turbo MC is not stepped so should work in the X config.

There are stepped and non-stepped MCs out there.
_________________
1994 Lotus Esprit S4 - Work in progress...
1980 Porsche 924 S2 DITC Turbo - Original spec
1978 Homo-Sapiens - Tired spec
1953 Landrover S1 - Pensioner Spec

fiat22turbo · Joined: 18 Jan 2006 Posts: 4040 Location: Portland, OR

I think after 79 all of the 924/44 used the X-style brake line routing, so you should be fine. Its just us poor slobs with the older cars that should reroute our lines.

I just did the reroute (because of the 944 brake upgrade and because of the compression fitting used to repair a brake line near the master cylinder, which is a no-no in my book) and it was a bunch of work. If you have an early car, try to find a donor with good lines to grab or you'll have to take your time and learn to bend brake lines (not that bad, just time consuming and a bit fiddly)

Just make sure you get the proper metric bubble flare fittings versus the more standard straight flare fittings. They'll fit up just fine, but may leak slightly if you mix/match parts. Which means if you can only get non-bubble flare parts in your area, that you'll need to make sure all of the parts match the type of flare you use.

I would also suggest getting braided brake lines for the flex lines, there are DOT-legal ones for those of you in the States and I think there are TUV authorized ones as well.

Edit: This article was in my inbox from Eastwood after I wrote the above:

http://www.eastwood.com/Brake_article

Timely, yes?
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Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

emoore924 · Joined: 13 Apr 2004 Posts: 2822

I think you'll also have to rig up a brake light switch if you want to use the later 944 style m/c. IIRC The later 944 style uses the switch on the brake pedal whereas the 79 has the two pressure switches on the m/c itself.

I did this conversion and rather than using the 44 setup, I used the m/c from the early 928 and I think from the 79 only turbo. That way I had the switches on the m/c to match the brakelight wiring but the bigger bore on the m/c (21mm maybe? or was it 23mm). Took a little bending on the brake lines and an extension to get them right but not a big deal (although the metric end-fittings are a bit obscure apparently). If you want pics, pm.

*edit

Here's the part # for the m/c that was the best retro-fit to the 79
part #: 928 355 011 04,
application: 928 78-84, 79 924 turbo w M471
23.81 bore
ATE

Other than one brake line, this will bolt right up.

There is no part # on the m/c itself. You have to examine configuration to determine which is which.

BTW, I have a nice spreadsheet showing the different m/c's and their applications. PM and I'll send it to you. And I'll try to host it someplace and post it here. But that'll be when I get a rountuit.

Joes924Racer · Posted: Thu Apr 08, 2010 2:45 am Post subject:

First it still works allright with the 924 mc and x worked I have a 44 mc
though never did it.. though I did make new hard lins off the rear.
Just the step from drums to disc and lots of bleeding with a bleeder pump.
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1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

emoore924 · Joined: 13 Apr 2004 Posts: 2822

Here's a pic of one of the setups I have. It uses 477 611 017 with the two pressure switches and one line on the top, two on the rear sides. This m/c would be from 1980, all vehicles, and does have the larger bore -- 23.81, installed in a 78.

Sent the comparo file to someone else who will host for us...