# Mk2 drum to mk4 disc conversion? Need some help



## deadheadsforvw (Aug 16, 2008)

Just to start did a bunch of research and have all the stuff ripped off and starting to go back on but running into an issue with using my mk4 carrier bracket am I suppose to use a mk3 carrier braket and mk4 caliper and pads and can't use the mk4 carrier?

Thanks
Justin

Appreciate any advice just not seeing that in any of the diys I have been reading


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## cuppie (May 4, 2005)

Hard to say, without knowing your full parts-on-hand list. 

The 'easy' way to do a rear disc conversion on a MkI or MkII: 
MkI-MkIII stub axles, rotors, bearings. 
MkI-MkII caliper carriers. 
MkIV calipers.
B3 Passat (*IIRC*) rear brake hoses. 
Brake cables appropriate to your vehicle. 
Like automotive Legos (because that's what VWs are!), it all just drops together (with the caveat of mounting the calipers upside-down.) 

This gets you rear discs, but maintains 4x100 wheel bolt pattern. 
MkIV stubs, bearings, and rotors are 5x100, and the rotors are larger diameter. Carriers are 'taller'; and, IIRC, the bolt spacing is different.


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## deadheadsforvw (Aug 16, 2008)

Thanks man got all the parts except was unsure on the carriers since the mk4 ones were not working 

I have bilstein febi stub axels
SS lines for mk2-mk4 conversion 
Mk4 rear calipers and carriers
Mk3 4x100 rotors 
bearings and all that
And the ebrake cables I need 

Just the carriers aren't fitting when rotors are on so tried to research a parts list on diys but wasn't finding anything on what specific carriers that need to be used


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## petethepug (May 25, 2001)

Just think Passat W8 when it comes to the hybrid brake lines
Rear Exact-Fit Stainless Steel Brake Lines  







$59.95 @ ECS or $44.95 w/o the banjo bolts

Click this write up. It has lots of good stuff like the quote below in it....Mk4 rear caliper swap completed - Pix inside. Damn it's an '03 write up and still solid



CdnDub said:


> bolts right up.
> even the mk4 pads will work.
> you need the mk2/3 style rear caliper carriers and stub axles and back plates, bearings, and rotors tho.
> altho i've heard mk4 rear rotors work just fine as well despite some being slightly larger 9" instead of 8.9"?


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## deadheadsforvw (Aug 16, 2008)

petethepug said:


> Just think Passat W8 when it comes to the hybrid brake lines
> Rear Exact-Fit Stainless Steel Brake Lines
> 
> 
> ...


Those are the lines I got just need help on what carrier to use


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## cuppie (May 4, 2005)

Stock. Use stock carriers for a MkII. 
I checked GAP yesterday; they have them for $55 each (and, includes the sliders & boots. Not bad...) 
http://www.germanautoparts.com/Volkswagen/Golf/Brake/354/1


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## deadheadsforvw (Aug 16, 2008)

cuppie said:


> Stock. Use stock carriers for a MkII.
> I checked GAP yesterday; they have them for $55 each (and, includes the sliders & boots. Not bad...)
> http://www.germanautoparts.com/Volkswagen/Golf/Brake/354/1




Sweet thanks buddy yeah was on there and a few other places last night but don't want to order anything till I found out what I needed greatly appreciate the help


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## germancarnut51 (Mar 23, 2008)

deadheadsforvw said:


> Those are the lines I got just need help on what carrier to use





That's a ridiculous price for the hoses.

I used FTE Brand hoses from a 97 Passat from europartsdirect.com on my MKIII for the MKIV rear brake conversion. They cost me $10 each on sale, regular price was $15 each.


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## germancarnut51 (Mar 23, 2008)

deadheadsforvw said:


> Sweet thanks buddy yeah was on there and a few other places last night but don't want to order anything till I found out what I needed greatly appreciate the help


I don't know if there is any difference between the MKII caliper carriers, and MKIII rear caliper carriers. If I were doing the conversion on a MKII, Id use MKIII caliper carriers, and use the calipers right side up, by flipping the parking brake cables, and brake hoses like they did with every model after the MKII.

I converted a number of MKII to rear disk brakes from rear drum brakes, and I don't remember mounting any of the calipers upside down when I did it. Maybe I mounted them right side up and flipped the brake cables and brake lines without even thinking about it.


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## 134hpvw (Sep 6, 2013)

did this to my b3 Passat. those lines for the early b5 cars are cheap enough new but hard to find at local parts stores here in canada


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## Njegos18t (Jul 31, 2007)

Did this recently on my mk2 I used the stock rear brake lines of a passat FWD I believe. The mk4 calipers are 4lbs lighter than cast mk2-3 ones, Also when you bleed the brakes make sure the wheels are on the ground because the proportioning valve almost closes with both wheels high off the ground I learned that the hard way haha


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## deadheadsforvw (Aug 16, 2008)

Appreciate all the input don't need the negative input on the lines I got you don't want to spend that much on your car that's fine. And yes found that the mk2 and mk3 rear carriers are the same. Issue I'm having is pedal is going to the floor. I used a power bleeder made for vw's and also pumped pedal and bleed brakes further didn't do on ground but on four level jackstands well seemed pretty level. Then put tires back on and started car and pedal goes to the floor. Heard I should upgrade to a mk3 or bigger master cylinder? Or would appreciate any other advise if you ran into the same problem and what you used to remedy it.

Thanks
Justin


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## 134hpvw (Sep 6, 2013)

if the mk2 master cylinder is original or unknown milaghe; the bleeding could have taken it into unused territory inside the bore and ripped the seals. so it is by passing inside.
when you pump it it builds pressure on the pedal; but when slowly pressed on it by passes internally.


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## deadheadsforvw (Aug 16, 2008)

134hpvw said:


> if the mk2 master cylinder is original or unknown milaghe; the bleeding could have taken it into unused territory inside the bore and ripped the seals. so it is by passing inside.
> when you pump it it builds pressure on the pedal; but when slowly pressed on it by passes internally.


So get a new master cylinder? Looks original so probably 180k on it


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## Njegos18t (Jul 31, 2007)

I would upgrade the master to a 22mm none Abs


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## deadheadsforvw (Aug 16, 2008)

Njegos18t said:


> I would upgrade the master to a 22mm none Abs


Sweet thanks buddy appreciate the input. I've read you can use bigger Audi ones or is the mk3 non abs 22mm one sufficient enough ?


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## Njegos18t (Jul 31, 2007)

Mk3 is plenty of stoping power make sure you bench bleed it before the install if you decide to change it


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## deadheadsforvw (Aug 16, 2008)

Awesome thanks again man appreciate the info


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## Dr.Jeff (Oct 30, 2013)

I'm just curious, if the swap uses Mk1-3 axles/etc and Mk1-2 carriers, then why use Mk4 calipers? Why not stay with the calipers that match the MK1-2 carriers and other parts?
I also did not follow the "flip the calipers upside down" logic. Why?
Don't get me wrong, I'm not questioning the validity of these things...just trying to learn why. I want to do the disc conversion on a Mk1 and appreciate the education.
Thanks.


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## cuppie (May 4, 2005)

Because the MkIV aluminum calipers are far, far more durable than the MkI-MkIII iron calipers (and, a little lighter, too.) 
And, if you're buying new ones, they're actually _cheaper_, too! 

The 'upside-down' is more something for a car that already has rear discs - unless you want to re-plumb the rear axle, and find the super-double-secret brake cables that will reach, it's a lot simpler to just mount the calipers inverted. Cables reach, and the Passat hoses JustFit. 
It's less of a problem for someone coming from drums, though - since you're already replacing the cables, and already have to re-do the hardlines on the rear axle, you have a better opportunity to mount them right-side-up than, say, I did on my Scirocco. 
(FWIW, I'm not sure yet how they'll mount up on my QSW. I'll find out eventually, though, as it needs new calipers due to Sucky E-brake Syndrome.)


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## germancarnut51 (Mar 23, 2008)

deadheadsforvw said:


> Appreciate all the input don't need the negative input on the lines I got you don't want to spend that much on your car that's fine. And yes found that the mk2 and mk3 rear carriers are the same. Issue I'm having is pedal is going to the floor. I used a power bleeder made for vw's and also pumped pedal and bleed brakes further didn't do on ground but on four level jackstands well seemed pretty level. Then put tires back on and started car and pedal goes to the floor. Heard I should upgrade to a mk3 or bigger master cylinder? Or would appreciate any other advise if you ran into the same problem and what you used to remedy it.
> 
> Thanks
> Justin




Just picking the car up on jackstands and holding the body level is not going to open the proportioning valve, and allow you to bleed the rear brakes properly.

You need to hold the rear wheels in the wheelwells where they are positioned when the car is on the ground and sitting on the wheels. You don't need to raise the front, that will not make any difference. The proportioning valve is on the rear axle beam and has an arm that moves as the rear wheels move up and down. This controls the amount of brake fluid allowed to flow into the rear brakes. The valve must be completely open, allowing unrestricted flow for you to be able to bleed the rear brakes. IF IT IS NOT, YOU WILL HAVE A MUSHY BRAKE PEDAL.

It sounds to me like you did not bleed the brakes properly. If you do decide to buy a MKIII master brake cylinder, I recommend the Meyle Brand Master brake cylinder for MKIIIs. It's only about $45, and it has an alloy body, so it won;t rust like the typical VW master cylinder.


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## deadheadsforvw (Aug 16, 2008)

germancarnut51 said:


> Just picking the car up on jackstands and holding the body level is not going to open the proportioning valve, and allow you to bleed the rear brakes properly.
> 
> You need to hold the rear wheels in the wheelwells where they are positioned when the car is on the ground and sitting on the wheels. You don't need to raise the front, that will not make any difference. The proportioning valve is on the rear axle beam and has an arm that moves as the rear wheels move up and down. This controls the amount of brake fluid allowed to flow into the rear brakes. The valve must be completely open, allowing unrestricted flow for you to be able to bleed the rear brakes. IF IT IS NOT, YOU WILL HAVE A MUSHY BRAKE PEDAL.
> 
> It sounds to me like you did not bleed the brakes properly. If you do decide to buy a MKIII master brake cylinder, I recommend the Meyle Brand Master brake cylinder for MKIIIs. It's only about $45, and it has an alloy body, so it won;t rust like the typical VW master cylinder.


Thanks man appreciate the info my master cylinder was definitely shot but will try te recommendation on the pro portioning valve

Thanks
Justin


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## Dr.Jeff (Oct 30, 2013)

I appreciate this thread, even though my intended conversion is for a Mk1. For some reason my attempts to "search" the forum for Mk1 rear disc conversions have not returned much (that's how I found this one). I'm certain there's been countless discussions on it, just not had much luck finding them. So I hope you do not feel I am hijacking your thread.

Thanks "cuppie" for the added information above.

Are all Mk2 and Mk3 rear calipers prone to the e-brake issue? Is it more of a 'cable' or 'caliper' problem?
My intended conversion will be on a Caddy Sport Truck, so the hoses/lines and e-brake cables will need to be redone regardless of what calipers I use.

If anyone happens to have links to good discussions on the Mk1 conversion please send them to me...thanks in advance.
Let us know how your conversion goes.
Thanks, Jeff


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## cuppie (May 4, 2005)

The MkI-MkIII iron calipers pretty much suck. 
They'll often develop one of two problems:
1- Sucky E-Brake Syndrome (doesn't really hold. The wagon has this problem.) 
2- lockup. (self-explanatory.) 

The MkIV (aluminum) caliper is quite a bit more robust. It's prettier, too.  

Cables are pretty durable - so long as neither the jacket nor the boot are damaged (either of which allows water to enter; bad happens after that - but, that's Cable 101), they're non-issues.

AFAIK, your conversion wouldn't be all that different than on a car - MkI-MkIII stubs, rotors, carriers. Cables, well.... it's a Caddy. Don't know there.


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## deadheadsforvw (Aug 16, 2008)

Dr.Jeff said:


> I appreciate this thread, even though my intended conversion is for a Mk1. For some reason my attempts to "search" the forum for Mk1 rear disc conversions have not returned much (that's how I found this one). I'm certain there's been countless discussions on it, just not had much luck finding them. So I hope you do not feel I am hijacking your thread.
> 
> Thanks "cuppie" for the added information above.
> 
> ...


Haha no worries at all man glad others can get some use from this as I have good luck with your swap


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## Dr.Jeff (Oct 30, 2013)

Thank you to everyone for the support and information. :wave:


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## deadheadsforvw (Aug 16, 2008)

So trying to finish this swap up now that the nicer weather is here and still my pedal is going To the floor after putting in the mk3 master cylinder. Do I need to change my brake booster I have solid fluid coming out of all bleeders with no air pockets. And using a motive brake power bleeder to push the air through And still goig to the floor. Any help would be appreciated.

Justin


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## deadheadsforvw (Aug 16, 2008)

I also bleed the brakes manually a few times in and hold while my buddy bleed and all brake fluid coming out no air on all four corners then start the car and right too the floor im stumped so I appreciate any help I know someone was saying the pro portioning valve but like I said smooth flow out of all corners 


Thanks
Justin


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## deadheadsforvw (Aug 16, 2008)

The car is level on the ground when doing this so proportioning valve is open really don't see what I'm doing wrong here I have done a lot of brake upgrades and replacements on my other vw's but really stumped here only thin I can think is bad brake booster


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## deadheadsforvw (Aug 16, 2008)

Bump any help?


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