Drum to disc swap questions

Hi all,

I am swapping out my drum brakes for a complete rear axle with calipers, lines, etc from a 2000 cabrio. My question relates to the prop valve. The new axle lacks one, presumably due to the ABS system on the Cabrio.

1. Is there a difference between the drum brake valve and a disc brake valve? I’m assuming if not, I can just adjust the old one to work with the discs.
2. Is it worth buying a new one? If so, what is the part number for a prop valve for disc brakes and no ABS?
3. Rear bushings look fine, zero cracks. Should I even consider swapping them out?

Many thanks.

According to the parts catalog the rear force regulator is different between drum brakes and disc brakes for vehicles without ABS brakes.

Drum brakes # 1H0 612 151
Disc brakes # 1H0 612 151C

What the difference is I do not know. I don't even know whether these part numbers above are current, you'll have to look them up to see if they're NLA or not.

Steve

They are still available, made by Ate, usually about $150.

If you are going through all the work to convert it, may as well do it right and get the right valve.

FWIW, I had bought new two 1995 Golfs. One, the "first" one, was an early 1995 car, so essentially a '94 with airbags, that was the Sport model (what Volkswagen called the GTI that year for us). In addition to other items different from the regular Golf, it had rear disc brakes, no ABS (although that was optional).

The "second" one I got, largely because I refused to share with my wife, was a later '95 Golf GL, which was closer to a '96 model in some ways (like it was cursed with the early DRLs, etc.). It had rear drum brakes.

Both cars' front brakes were the same.

I can tell you that driving both cars, there was very little difference in stopping power, and to be honest, the pedal feel was actually a little better on the drum brake car. I'm sure driven at their limit, the disc brakes would not fade as much, but drums are actually pretty efficient at stopping a car, especially one like the A3 that was still very front biased.

If you really want to upgrade your brakes, the 5 bolt VR6 cars have FAR better brakes, because their FRONTS are much larger. I also had a lot of experience with those, too, and my sister bought a new 1996 Jetta GLX, so I had plenty of opportunity to drive them all back to back.

Good news is, I think once the rear disc conversion is done, the conversion to 5 bolt is pretty easy on the back axle.

The A3's rear calipers are a common problem regarding sticking, too. So make sure they are actually in good order or just buy new ones.

Thanks for the help, gentlemen. The main reason I am doing the swap is because the rear beam is bent, not really for braking performance. I haven’t gotten up the muster to go full GLX conversion and the 4-lug suspension is working just fine for me so far.

Bent beam is a good enough reason to swap for sure!

Yes, bent beam is a very good reason to replace.

The other downside to the rear disc is that these calipers are problematic back there over time where as drums are less so.

Good luck!

Steve

One more dumb question. I have purchased the new prop valve. I am looking for the Allen head bolts that hold it to the bracket but I cannot secure a part number. Figure it would be smart to have some new hardware on hand in case this thing is seized. Does anyone have a P/N for the mounting bolts?

N90729401 is part number for the m10 allen bolts that hold the caliper carrier to the stub axle.

Be sure when you install these that you turn the caliper piston while you are forcing it to retract for the new pads, if you don't you'll ruin the parking brake mechanism inside.

Good luck!

Steve

Thanks for the note, Steve. The bolts I’m referencing are different - they are the chamfered Allen head bolts that supposedly always strip or seize into the prop valve. I can’t find a part number anywhere.

N10299503 m8x58

Just a mounting/positioning bolts? As long as they didn’t meet a fluid channel, I’d drill it out and make it a through bolt hole.

VW probably wants $10 each.... I’m going to the stealership and paying &4.50 for a c-clip... if it wasn’t in my trans, I’d risk reusing the existing clip.

-Todd

ToddA1 said:

Just a mounting/positioning bolts? As long as they didn’t meet a fluid channel, I’d drill it out and make it a through bolt hole.

VW probably wants $10 each.... I’m going to the stealership and paying &4.50 for a c-clip... if it wasn’t in my trans, I’d risk reusing the existing clip.

-Todd

Click to expand...

Todd
What trans clip is that you're talking about.

Steve

5th gear clip, for a 020. I’m doing a 5th gear swap....

-Todd

ToddA1 said:

5th gear clip, for a 020. I’m doing a 5th gear swap....

-Todd

Click to expand...

Oh, sorry, no 020 parts

Steve

ToddA1 said:

Just a mounting/positioning bolts? As long as they didn’t meet a fluid channel, I’d drill it out and make it a through bolt hole.

VW probably wants $10 each.... I’m going to the stealership and paying &4.50 for a c-clip... if it wasn’t in my trans, I’d risk reusing the existing clip.

-Todd

Click to expand...

Surprised, Ellis VW only wants $1.31 for them, but that doesn't include the postage either.

My VW dealer would probably want $10 for them, they're notorious gougers.

Steve