Help! What is this?

[plimthing]

So first, apologies as I cant upload a photo just yet.
I'm in the middle of my 72 crossover project and ive discovered something that I'm not too sure about. Its in the braking system and lives on the right hand side ( underneath van, obviously), further back than the master cylinder. Hydraulically its between master cylinder and rear brakes. Its help to chasis rail by two bolts. As for the number of hydraulic connections, I'm unsure as i have empty ports on the thing.
I have a part number that's not recognised by VW heritage, JustKampers over here in UK- 211 612 501 (?) that's the best i can make it out to be, but I'm 99% sure its correct,
I'm thinking somekind of bias valve to give more braking pressure to front brakes?
Also, if anyone knows what it is, can anyone help with the routing of pipes please. As i said i have missing fittings and crimped of pipes on mine.7
Thanks For Help
Tony

[kreemoweet]

It's the brake pressure regulator, which reduces pressure to the rear brakes, and does so to a greater extent
when the vehicle is being braked hard. It's supposedly intended to keep the rear wheels from locking up and
causing "directional instability". Only used on vehicles with front disk brakes.

There were two versions, and the part no. you give is for the earlier one. Line from the M/C connects to
the rear port, and line to the rear brakes connects to the front port. There was a Residual Pressure Valve
on the front (I think) port, and if it's missing you'll have to find one or an adapter, because the brake line
union nut won't fit directly into the Pressure Regulator.

Your Bentley manual has some info on these items.
_________________
'67 bug: seized by the authorities
'68 bug: seized by the authorities
'71 kombi: not yet seized by the authorities

Stop dead photo links! Post your photos to The Samba Gallery!

[Abscate]

Treat those carefully as they arent available anymore, TTBOMK
_________________
.ssS!

[plimthing]

Thanks for info, I'm going to presume it still works and refit it. The valve at the front is missing, so I'm not sure what I'm going to do there.
Would it be rude to remove it completely? Can you buy the valve that's missing anywhere. I've got no info on it from vendors I use in UK.
Tony

[kreemoweet]

The r.p.v. would probably only be available used. VW had them on most master cylinders of the era, but
discontinued their use in the early-to-mid-seventies. Perhaps they were used on other European car makes of the period.

Here's a topic that has nice photo's of what you'd be looking for:
https://www.thesamba.com/vw/forum/viewtopic.php?t=476304

I don't think a functional r.p.v. is actually necessary, but you'll need at least the shell or a similar-threaded adapter.
VW of America (I think it was) came out with a service bulletin regarding wimpy bus rear brakes, and a part of one of the procedures
they outlined was to gut the r.p.v. (as the thread above discusses). I followed that procedure, and ran my '71 bus with
no r.p.v. for many years, and it didn't seem to affect anything one way or another.
_________________
'67 bug: seized by the authorities
'68 bug: seized by the authorities
'71 kombi: not yet seized by the authorities

Stop dead photo links! Post your photos to The Samba Gallery!

[plimthing]

thanks for all the usefull info... i think I'm going to ditch the R.P.V and get the regulator fitted with an adaptor to accept brake pipe fittings.
onwards and upwards!

[mainstreetprod]

On that note- I'm new to VW buses and wondered what percentage of the braking is done by front/rear brakes on a bus? I know on any car with the engine up front, it mostly done by the front brakes and if your rears go out you can hardly tell. . How does rear engine configuration change the equation?

[plimthing]

Just looked at my regulator, it has a fitting already in the end connection, not sure if its an integral valve or just an adaptor. I'm going to leave it in place flush it through with fluid (fwds and back) and go for it!