My own Rear Disc conversion

[steveo9007]

VW T25 Rear Brake Disc Conversion for 15” wheels or bigger

What follows is my own rear brake disc conversion for the T25. I will add photos where necessary and document everything I have done to make this conversion go as smoothly as possible so it can be achieved by anyone that wants to take on this task. The reason for doing this conversion was so I wanting to bring the rear brakes up to a newer standard than the old and much unused drums that no longer appear on vehicles of today.

DISCLAIMER This document is provided for guidance purposes only, and therefore, the installation is carried out at users own risk. Be prepared for potential repairs as you find your way during this conversion.

Parts required :-
You can buy parts from various outlets of your choice as long as they come from a reputable place you should have no issues, all parts are sourced from vehicles belonging to the VAG type with exception of the adapters used to hold the callipers to the trailing arm Hubs.

Adapters :- From Epytec Part Number 352
VW T3 BUS Rear axle brake adapter Girling 38 Brake disc transformation 268x10mm Brake caliper adapter

Discs :- From Epytec Part Number 1927032381-LR
2x VW Sharan 2.8 VR6 Syncro 1.9 TDI brake discs housing 268x10 Ford Galaxy Seat Alhambra

Calipers :- Unbranded Part Number 8N0615423
VW Golf MK4 1998-2005 1.4 1.6 1.8T 1.9 TDI 2.0 Rear Disc Brake Calipers

Caliper Brand TRW Part Number BDA267
Carriers :- REAR BRAKE CALIPER CARRIER BRACKET GOLF MK2 MK3 GTi VR6 CORRADO G60

Caliper Unbranded Part Number M10 x 1.25 x 20mm
Carrier Bolts:- High tensile grade 8.8 hex bolt x4 ( Some might say go higher in grade bolt, that's your choice)

Disc Pads :- Unbranded Part Number 1H0698451G
VW GOLF MK3 GTI CORRADO VR6 G60 PASSAT B4 REAR DISC BRAKE PADS SET

Handbrake :- VW Part Number 191609721F
Cable Handbrake Cable – Mk2 Golf/Jetta

Handbrake Vw Dealer Part Number 1H0609747
Cable clip Clip x2

Wheel Stud:- Vw Heritage Part Number AC601SS45
M14 x 1.5 45mm Press

Brake pipe :- Rear Braided Part Number BRT Motorsport made to order
Brake Lines

Split Pin :- VW Part Number N0125482
Split Pin - T3 Rear Hub

P Clips :- VW T3 Handbrake Part Number N0206093
Cable x6

This is for the basic parts you need, there may well be other parts that I have not included, it also does not include the renewing of the spring plates. The price also Excludes machining of Rear wheel Hubs which need to be done to fit inside the new discs, the rear hub nut was reused as it was brand new on inspection.

Tools Required :-

Not a full list but enough to get the job done there may be others but it is all down to each ones individuality, the most common ones are here.

46mm Impact Socket 46mm Slogging Spanner Long Nose Pliers
13mm Spanner Axle Stands x2 Trolley Jack
Wheel Chock x2 10mm Spanner Dot 4 Brake Fluid
Rag Torque Wrench 500Nm Socket Set
Hammer Screwdriver set Impact Gun



Starting your work :-

Be prepared to rectify anything that is broken or damaged when dismantling your drum brakes from the trailing arms as you will see further down in this write up.

First that is required is for the hubs to machined down to fit inside the new brake rotors/discs. I took mine to a machine shop where they took 15mm of the circumference, I left the brake discs with them so they made sure they fitted.

Once this has been done you will need to remove the original studs and replace with longer studs as the thickness of the brake disc and wheel will make the original studs too small, this is if you haven’t got longer ones fitted. I done this in my shed myself as I bought a stud tool to assist in pulling the new studs through, I also used 3 hardened M18 washers to stop the tool getting caught on the stud splined shank.

Next process is to strip down and remove the old drum system from the trailing arm, and release the handbrake from the balance bar. See Below.

Once this is done I took the liberty of cleaning around the hub and inspecting the spring plates at this stage as access is very good, if you need to replace the spring plates now is the time. This will involve welding a new plate onto to the trailing arm as you can see in the next set of pictures the damage of my old spring plates.

Removing the old spring plates was easy enough with a chisel and then cleaning the area up ready to offer the new plate in position.Next was to weld in position and paint to protect the trailing arm and the new spring plate.

I bought my own MiG welder, I did get someone to price up how much it would cost and they was going to charge £180, a decent welder only cost £250 approx, so if your confident enough to do it yourself I would. The next stage that can be done is to start fitting the conversion parts to your trailing arms, here I have fitted the adapter plates and machined hubs. You can also see that I painted the trailing arms with Rust protection paint

So we have new spring plates, and also spring seats in place. You can see the bolts used for fitting the adapter plate, I used the same torque settings that were used for the same bolts on the drum brakes. Now its time to fit the discs and the caliper carriers to the adapters.

As you can see the disc clears the edge of the caliper carriers nicely, now we can fit the calipers to the carriers and put the pads in place.When fitting the discs it is also a good idea to fit the bolt that holds the disc to the hub, for this it was an M12 thread that needs to be drilled and tapped in the hub, so line the disc up to the hub and make a mark and then drill a hole to thread an M12 tap into it. This stops the disc from moving away when the wheel is removed.

Next is to fit the brake lines to the flexi hose at the bulkhead, for this I went to www.brtmotorpsort.co.uk and ordered a made to measure set. Measurements were 680mm long, bulkhead M10x1 fitting, Caliper end was a M12x1 90 degree angle. See below

This makes is look cleaner and tidier than manually bending the original brake line that was fitted to the hub and then to add another flexi brake line from that to the caliper. I was confident at this stage to put the wheel on and torque up the hub nut to 500Nm and then insert a new split pin into the stub axle.

For the handbrake I had a shop around and found a good working solution without having to cut or add anything to the existing setup, I found a suitable cable which originally belongs to a VW Golf Mk2 / Jetta 88-92 Rear Disc brakes, it needs to be this one as it’s got the correct attachments and the length is correct between the caliper and the rear supports. Part Number at start of this instruction. As shown below laid on floor.

As you can see above, you will need the clip that holds it in place on the caliper and stops it moving away this is bought direct from VW dealer in your local area.
Next is to place the cables into the balance bar and I threaded a 10mm nut on to the ends and then another 10mm nut on the other side to hold in place on balance bar and then tighten up on the usual central nut so the cables are tight but not to tight to put the handbrake, a quick spin of the wheel should let you know when enough is enough.

Then all that is needed is to place P clips in same place as original handbrake to hold the cable of the ground so it doesn’t snag anything as you drive along. Bleeding of the braking system must be completed once you have fitted all parts and a visual and mechanical check of all components that have been fitted must be done before starting out on the road, you will also have to adjust the balance bar on the handbrake to take out the slack of the cable before it starts allowing the pad to bite on to the rear discs. Also out of interest I am going to book my van in for a brake test to see how the rear discs compare.

In summary :-

I looked around to see who was selling this kinda of kit, I was finding some kits upwards of £650 all parts including and having some mechanical knowledge I thought I would take this task on myself and see what the outcome was, as you can see the price difference is a lot, obviously excluding the rear spring plates to be renewed it was almost half the price. DON’T FORGET TO SHOP AROUND, YOU HAVE THE PARTS LIST SO DON’T BUY FIRST TIME, I DID ON SOME ITEMS AND PROBABLY COULD HAVE GOT THEM CHEAPER.

NOW ALL I HAVE TO DO IS CHANGE THE PADS WITHOUT GOING THROUGH THE HEARTACHE OF MESSING AROUND WITH A DRUM BRAKING SYSTEM.

Reference Places and parts outlets.

Below are places I read on how to do this conversion and got all my info from so credit to them where necessary. Also from various people with in the VW T25/T3 community on face book.

www.club80-90.co.uk
www.gowesty.com
https://www.facebook.com/groups/160381628934102/
www.epytec.de
www.brickwerks.co.uk
www.smallcar.com
www.ebay.co.uk
www.brtmotorsport.co.uk
www.thesamba.com

If you need assistance in any specific area of this disc conversion, then I am more than happy to help.

[dobryan]

Nice write up!

That was a lot of work.

Thank you.


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Dave O
'87 Westy w/ 2002 Subaru EJ25 and Peloquin TBD

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[steveo9007]

[Steve M.]

Good on you!
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[?Waldo?]

I have a couple Mk4 TDI's that use the same calipers and in the Mk4 the e-brake works great. I have heard people in Vanagonland complain that their e-brake does not work well after conversion to the rear discs. Does yours work well? Will it hold the van well on an incline?

[Surfwagon]

Looks great! Will be saving this thread for the future.

[Italjohn]

Excellent, I have been looking for something like this for ages.
Thank you for adding all part numbers too


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[steveo9007]

[Butcher]

Do as you wish, but over 40 years of working on Mercedes, BMW's, and a few VW's, there has never been a car that uses 8.8 grade bolts that secure brake parts to the suspension. You should replace those bolts ASAP.

[[email protected]]

Outstanding, thanks.

[Gnarlodious]

[steveo9007]

[steveo9007]

[Butcher]

You have been told wrong and there are not plenty of cars with 8.8 mounting bolts. Advising others that using poor quality bolts is not ok or responsible.

Thinking that it's just the rear brakes and that will be ok is foolish too. What do you think the car will do if the caliper wedges up to the wheel and locks the wheel up? There is a reason that the factory spends a lot of money to lock the front brakes first.

Sorry to sound so harsh but this thread will be around a long time. If you can't do it right or you think it's good enough, tell that to Johnny's parents when you hit him.

You come up with this home grown brake system that is not even tested or engineered to work on your Vanagon. You are saying this system is good enough to travel the public roads without the needed testing. Can you imagine if the factory had this type of attitude? Do yourself and the rest of the world a favor, put the right grade bolts in.

FYI, many of us do the same thing so you are not alone. You just need to take brakes seriously and not accept other opinions as fact. I have never ever seen 8.8 grade bolts used for brakes. Thinking they are less brittle is a foolish thought.

Brakes are a pet peeve of mine. So many people attempt to fix their own brakes and have no clue what they are doing. Then there are others that attempt to do something the factory would spend millions to test and they have done a two mile road test and call it good.

Do yourself and the others on the road, order the right bolts or at edit your post so that others that may follow your lead does it correctly.

[vandroid]

Butcher, thank you.

[steveo9007]

[?Waldo?]

Steve, I really appreciate your post. Thanks for taking the time.

I would mention that you can click on any user's username and it will take you to their profile. In the Avatar section is the option to "add to your ignore list". If you select that option then in the future when you are reading the forum, posts from that user are not displayed and instead there is this message: "Click to show hidden post from this member on your ignore list." I have found that actively using the ignore list can significantly improve the Samba experience.

[SteveVanB]

Awesome write-up! Thank you!
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[ragnarhairybreeks]

Hi,

Very much appreciate you posting your work. Thanks !

Couple of questions.

Can you give me a rough guess of the effective wheel offset change added thickness of the rotor ( versus the old drum) ?
I’m guessing maybe 5mm?

And the epytec adapter plates... they are pocketed where they sit on the bearing housing. But it doesn’t look like a close fit pocket. I’m thinking the pocket is to place the face of the adapter where it needs to be for the brake carrier but still having a fair bit of meat on the rest of the adapter ( what is it, about 10mm thick material?)

Thanks again for posting your work.

Alistair
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[steveo9007]