Rear brake pipe replacement

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Joined: Mon May 16, 2011 6:48 pm
Passat model: 1741 estate 1991

Rear brake pipe replacement

Post by pointer » Tue May 08, 2018 6:54 pm

I've started replacing rear brake pipes and hoses on my 1991 Passat estate but I'm not sure the size of the male unions for the pipes. I can get 3/16 copper pipe almost anywhere and I've bought the hoses but there appears to be two different sizes for unions for the pipe, 10mm and 12mm, but which is correct for my vehicle. ? :-? If it helps, the union connecting the rear brake cylinder has a measurement approx. 11.2mm across flats, so possibly 10mm unions (?).

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Passat model: B5.5 H'Line Est
Location: Maidenhead Berkshire

Re: Rear brake pipe replacement

Post by ct.p » Wed May 09, 2018 8:31 am

I'd say metric flares and 10mm metric fittings, mostly. I know on the more modern stuff they did use a larger fitting here and there, mainly on ABS pumps to avoid cross / wrong connections.

Also if you haven't already bought it, use Kunifer or Copper Nickle tube rather than copper. Only a few quid dearer for a 10m coil but is much, much better, primarily because it won't case harden and split like copper can.
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Passat model: B3

Re: Rear brake pipe replacement

Post by maclee » Wed May 09, 2018 7:08 pm

3/16" = 4.7625mm

These screenshots from the 1991 parts list might help you:

I love it that some of these items still use the original Type 1 (Beetle) part numbers (starting 111 & 113), while the connecting piece (item 1) has a T4* part number (starting 411).

*T4 meaning Type 4, (the 411 / 412).
412 variant.jpg
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Passat model: B3 TDI Variant
Location: Ammanford Wales

Re: Rear brake pipe replacement

Post by Zed. » Thu May 10, 2018 10:40 am

iIrc, all brake pipe fittings on B3’s are m10 x 1 :-s

the only exception i can think of being possibly on the abs assembly (if fitted :???: )

Rich. ('89 B3 tdi'e wagon :oops: '87 mk2 Golf now AHU tdi/02a etc. converted. '95 B4 tdi wagon. '95 T4 now 1Z t'Die converted. etc. ). '91 Landrover Discovery 200tdi 3door. '93 Landrover Discovery 200tdi 3door. '78 Chevette Hs rallycar project. '65 MG Midget. '91 Eunos Roadster 1600.

Posts: 59
Joined: Mon May 16, 2011 6:48 pm
Passat model: 1741 estate 1991

Re: Rear brake pipe replacement

Post by pointer » Thu May 24, 2018 8:37 am

Thanks to all above. :ymhug:

I had already bought copper pipe and some 10mm unions, so I pressed ahead ! I also bought a flaring tool from Toolstation but that simply scoured the pipe so it leaked !!!

I had the local garage make up a length of pipe for me and that fits perfectly. I managed to get a refund from Toolstation as I considered it faulty. Finally, the car got through its MOT retest on the 10th working day after the initial test \:D/

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