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86 jetta GL with rear drums. I will buy new rotors. So what do I need? Calipers, lines, what else?
 

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Re: What do I need to convert to rear discs? (Slytle)

Excerpts from a recent e-mail I sent --
For the rear beam, you can grab just about any disc-equipped rear A2 VW beam to fit in under your GTI.
The big thing with the rear beams not fitting is in the proportioning valve. A base Golf has a different prop valve than a GTI or a Jetta car. Since you have a GTI, your prop valve is at the beam mounting point on the body.
My base Golf did not have a prop valve there, so I had to add one...when I went to add one, I saw I needed a different beam (GTI/Jetta style, like yours).
With your car, for rear discs, all you really need to grab from a disc-equipped car would be the stub axles that bolt to the beam trailing arm ends, and the stuff that is on the stub axles (calipers, rotor, bearings, backing plate/dust shield). No need to swap beams on your car....just put on stub axles and the disc brakes. The only thing you MIGHT need to do is to put a few brake lines in...and actually, you may even be able to re-bend your current rear lines. You would only need to run 2 short pieces of brake line in the very back, because your hard lines now are bent to fit into the drums there currently....re-bend them to fit into the disc caliper. Worst case scenario is you would bend a new piece (you can buy pre-flared lines at the auto store, just bend to fit your car) from the beam mounting point on the body on the passenger side to the pass rear caliper, and another short piece for the drivers side rear caliper.
And --
But anyway, rear stub axles and all hardware on them for rear disc swap....from just about any of the A2 or A3 rides. Oh, e-brake cables are different too, you'll need to get the cables too. Front knuckles and hardware from an A3 for 10.1 brakes in front....same deal, but buy 11" calipers and rotors for 11" brakes up front.
I am pretty sure this is all correct, but in case I have forgotten something, run the idea past some parts people or other VW folks first

A side note....if you go to rear disc, it is advised you change over to a larger MC....you should have a 20mm unit now, you want a 22mm unit. I got one for $57 new (German, ATE) from Adirondack. If you go to 11" fronts, it is advised you go with the 22mm MC....if you go 11" and rear beams both, I think you might have to go 22mm MC, otherwise, the brakes will suck....I never tried it, I just went ahead and got the 22mm MC!
Good luck, and I hope this helps!
Also, I made a page showing my brake swap in back at http://wsd.dynip.com/Broke/rbrakes/rbrakes.html and fronts at http://wsd.dynip.com/Broke/brakes/brakes.html

Broke
 

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Re: What do I need to convert to rear discs? (Broke)

As usual Rroke provided good info for you. http://****************.com/smile/emthup.gif one thing to note: you have to swap all the lines from the prop valve back. The discs are designed to work a little differently and require a soft line over the axle instead of a hard line. Your best bet is to find a car to get everything off of from the prop valve back
 

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Re: What do I need to convert to rear discs? (1987&2001Jettas)

Sure enough they do

1987&2001Jettas is right, the discs do have the extra rubber lines right at the end so you can change pads....I looked under my cars, and right on the trailing beam of the axle, there is a small bracket, it looks like it is just tack welded onto the trailing arm, but the bracket is where the hard line ends and the soft line begins. On my 88 Rocco, the bracket is bolted to the trailing arm.
On the drum beam, there is no bracket of course, and the hard line leaves the beam pivot point, follows the trailing arm, and ends up on top of the triling arm, and it then enters the top of the drum.
In reality, all you would need to do would be connect your new rubber line and caliper to the hard line that used to feed your drum. Your hard lines from the prop valve to the beam pivot points should remain the same, then they should both turn to rubber like they do now, then back to hard lines, and that is it on your drums...but add a rubber line to the end, add a caliper, and you should be golden. The hard line on the disc rides stops on the bottom of the trailing arm, and meets the rubber line, your hard line is on top, and goes into the drum. Either score the hard lines and see if you can get that bracket (all the bracket really is is a metal piece with a hole drilled in it, hard line on one side, rubber on the other, one of those spring loaded things to keep the union tight. It looks very much like this (this is the beam pivot point though):

I'd grab the hard lines that are on the disc donor beam...follow them until they meet the rubber line that feeds the caliper...notice that bracket on the trailing arm...see if you can get it off. You'll be replacing the hard lines from the beam pivot points to the calipers, and the stub axles and stuff too....

I better send this link to this thread to that guy I sent that e-mail to now

Broke
 

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Re: What do I need to convert to rear discs? (Broke)

am i reading this correctly, if you have a jetta with rear drums and want to convert to rear discs, it is not necessary to swap beams?
 

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Re: What do I need to convert to rear discs? (BlueA2Jetta)

no beam swap http://****************.com/smile/emthdown.gif
 

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Re: What do I need to convert to rear discs? (Slytle)

i have the 16v booster and pedal assy that im about to sell on ebay or something, shoot me an offer if youd like it. http://****************.com/smile/emthup.gif
[email protected]
 

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Re: What do I need to convert to rear discs? (BlueA2Jetta)

quote:[HR][/HR]am i reading this correctly, if you have a jetta with rear drums and want to convert to rear discs, it is not necessary to swap beams?
[HR][/HR]​
From what I've experienced and read/been told, going rear discs does not require a full beam swap. If you have a base Golf, then you will not have the load adjusting prop valve (like those found on GTIs and Jettas)....instead, there are 2 inline valves right next to the MC. I think somebody tried the rear disc swap and kept their GL inline valves, but don't hold me to it

The rear disx stuff, I've been told over and over, all reside on special stub axles, which will bolt to any beam.
You already have one brake line each going to each rear wheel, so adding calipers just means hooking them up to the brake lines, and giving them a place to ride. Hooking them up to the lines isn't too awful tough, just screw them together....VW had a bracket at the end of the trailing arm so the rubber line and hard line can meet at one spot and not move, they used re-designed stub axles to hold the caliper and rotor and so on, and that is about it.
To do it just like VW did it, you need the prop valve that is load adjusting (at the beam pivot point), and you need the stub axles, and you need the little bracket where the 2 lines join. The little bracket I think you could get away without using...as long as the union doesn't hang so low you catch it on things driving, and as long as you don't let your caliper fall and hang when changing brakes, you should be OK without the little bracket....I would think....but I never tried it

If it wouldn't have been for my base Golf prop valves, I would have switched just the stub axles myself, but I wanted that load sensing prop valve, so I had to change beams completely, remove the inline prop valves that came with my car (that made the rear lines too short, once the 2 inch valves were removed), cut/flare/bend new hard lines from the MC to the prop valve, and new hard lines from the prop valve to the rear calipers

I took the chance to go ahead and replace other old parts like the rubber lines with SS, and I dumped my 20mm MC in favor of a 22mm unit.
So, in some situations, you can get away with not swapping beams

Broke
 
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