Rear Disc Brake Swap (306 Stub Axles, Hub, Discs and Calipers

[camarda 0]

Before I go ahead and buy the following parts, I just want to make sure they all will fit fine.

 

I have a 205 GTI 87 model 1.9 however the Australian Model has drum rear drum brakes and given I am doing an mi16 swap and will track the car I do not want to experience brake fade when the drums overheat.

 

Calling my goto wreckers they have put together the following parts as a kit to bolt into the 205.

 

306 Stub Axles

306 Hubs

306 Discs

306 Calipers (I am assured they are in good working order)

306 Pads

 

Am I able to literally bolt off and bolt on these parts and attach the brake lines from the drums directly to the calipers, bleed the system and have working rear brakes or is there more to it.

 

Cheers.

 

 

Edited February 28, 2022 by camarda

[Tom Fenton 1,525]

Its a straight forward enough conversion. You will also need the caliper mounting plate that will be on the 306 trailing arm. The brake hard line will not reach, you will need to make another (longer) pipe. You will also need 205 GTI 1.9 handbrake cables. Sometimes the stub axles can be hard to get out of the trailing arm and you may need to remove the arm from the car and press the stub axle out.

Arguably you may be better off to buy the trailing arms off the 306 complete and then fit to your beam.

[camarda 0]

Ok, hopefully they aren’t too hard to get out. I’ll talk to wrecker tomorrow and see what he says about 306 trailing arms.

 

With the longer brake line, where can I source this? do you have any info on rough dimensions, if it could reach the drum why doesn’t it reach the caliper in the same spot?

How does the handbrake cable attach?

 

[pug_ham 240 3 Cars]

7 hours ago, camarda said:

With the longer brake line, where can I source this? do you have any info on rough dimensions, if it could reach the drum why doesn’t it reach the caliper in the same spot?

How does the handbrake cable attach?

 

According to the parts catalog, the brake pipe needs to be 600mm long, the one for your car having drums is approx 550mm.

 

I'd hazard that if you measure along the same path from the flexi around the beam to the back edge of the drum back plate, that's what you'd get also.

 

The handbrake cable attaches to the bottom of the caliper & hooks through a little arm also on the caliper which activates the piston.

 

g

 

 

[Tom Fenton 1,525]

17 hours ago, camarda said:

Ok, hopefully they aren’t too hard to get out. I’ll talk to wrecker tomorrow and see what he says about 306 trailing arms.

 

With the longer brake line, where can I source this? do you have any info on rough dimensions, if it could reach the drum why doesn’t it reach the caliper in the same spot?

How does the handbrake cable attach?

 

Because the caliper fluid port isn't in the same place as the drum wheel cylinder fluid port. Which you will see when you look at the parts.

[camarda 0]

Ok, my wrecker is giving me the 306 brake lines as well which should be long enough to reach.

He doesn't have any handbrake cables, do any of you have part numbers or dimensions so I can order these on ebay or get them made up.

 

Just to be clear on the details before the following questions, I am leaving the stock Australian 1.9 Phase I Front brakes and putting 306 rear brakes on to replace the drums.

 

I spoke to a few mechanics including my main one as with brakes I would rather be safe than sorry with doing it myself.

They all have several questions that they need to know before agreeing to doing this swap as they have never done anything like it before. 

• Can you just attach the brake lines directly to the system with the existing master cylinder, as drum brakes work differently, whats the deal with compensator valves etc. do we just remove the compensator valve entirely and run the lines directly.
• Is the existing master cylinder strong enough to run both front and rear discs.
• Any other details needed to know about the plumbing?
• Essentially, aside from bolting on the new hub and stub axles, having the right length lines and cables, what other nuances are there. 

Appreciate the help.

 

 

Edited March 2, 2022 by camarda

[Thijs_Rallye 86 4 Cars]

1 hour ago, camarda said:

• Is the existing master cylinder strong enough to run both front and rear discs. 

The disc braked MC has four ports and is separated diagonally, grouped as right front and left rear, left front and right rear. If I remember correctly the MC diameter is identical, so you could also work with a T to the rear axle, although that introduces a potential single point of failure. You can look up the part numbers and dimensions on websites as autodoc to verify diameters.

1 hour ago, camarda said:

• Any other details needed to know about the plumbing?

You will need the brake pressure limiters as well for a disc conversion. Otherwise the axle potentially be over-braked.

 

Edited March 2, 2022 by Thijs_Rallye

[welshpug 1,622]

leave the valve and the hard lines alone bar the pair on the trailing arms,  MC will be fine as will the pressure limiter.

[pug_ham 240 3 Cars]

As said, just replace the brake lines where they meet for the trailing arm at the flexi by the lower shock bolt bracket. along the radius arm to the caliper.

 

You shouldn't need to change anything forward of this point on the brake lines.  

 

12 minutes ago, welshpug said:

MC will be fine as will the pressure limiter.

I agree the master cylinder should be fine but I'm not sure what the rear brake limiter set up is on the Austrailian models.

 

The 1.6 GTI has a single line to the rear with an inline compensator in the engine bay that will be fine with the change to rear discs but lower spec UK models had a pressure limiter built into the rear drum cylinders. 

 

These can be easily identified by the size ofthe brake pipe union going into the backplate on the drum into the wheel cylinder, if it's a 10mm union then you have a separate compensator elsewhere inline but if they are a 13mm union, they have the limiter built in.

 

g

 

 

 

[Gohn 62]

these are the part numbers for the handbrake cables you were after

 

Left:    474567

Right: 474568

 

you can check 205 part numbers in future at:

 

miamistu.co.uk

 

I haven't ever owned a GTi

but from what I understand the early versions had a braking setup same as the UK 1.6GTi, ie rear drums and an inline compensator

the later versions had the full 1.9GTi package with rear disks

you'll still need to check on Graham's suggestion above to confirm, but because yours is an '87 it should have come with the inline compensator

17 hours ago, pug_ham said:

I agree the master cylinder should be fine but I'm not sure what the rear brake limiter set up is on the Austrailian models.

 

The 1.6 GTI has a single line to the rear with an inline compensator in the engine bay that will be fine with the change to rear discs but lower spec UK models had a pressure limiter built into the rear drum cylinders. 

 

These can be easily identified by the size ofthe brake pipe union going into the backplate on the drum into the wheel cylinder, if it's a 10mm union then you have a separate compensator elsewhere inline but if they are a 13mm union, they have the limiter built in.

 

g

you could try your local peugeot place with those part numbers.. or ebay