Freddie17

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Just to be on the safe side, I’m considering upgrading all my vac lines - they look like the originals, and whilst I don’t think any have worn through, I don’t actually know what condition they might be in.
Looks straight forward enough, but here are the questions;

How do I identify all of them?
What is the best line to replace it with (size / temp rating etc.)

I’ll also be doing the main air pipes - is there a kit for these that doesn’t come in blue or orange? ;)

TIA
 
1233_014730864.jpg

1233_014729120.jpg

https://cat.lrparts.ru/images/diags/12/1233_014729120.jpg

https://cat.lrparts.ru/images/diags/12/1233_014730864.jpg
 
How do I identify all of them?
follow the line that comes from the vac. pump,
which is .. standing in front of the engine .. on top right of engine,
driven by the camshaft.
main hose .. with non return valve .. goes to the brakes servo .

other hoses that branch off the main .. will go to :
vac reservoir > turbo solenoid
egr solenoid
...
4mm i.d. silicon hoses work well
..
careful removing the old one from the turbo vac. reservoir ..
as the spigot can break .. epoxy glue be a fix .. if it does break.
.
 
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follow the line that comes from the vac. pump,
which is .. standing in front of the engine .. on top right of engine,
driven by the camshaft.
main hose .. with non return valve .. goes to the brakes servo .

other hoses that branch off the main .. will go to :
vac reservoir > turbo solenoid
egr solenoid
...
4mm i.d. silicon hoses work well
..
careful removing the old one from the turbo vac. reservoir ..
as the spigot can break .. epoxy glue be a fix .. if it does break.
.

4mm silicon hoses… what internal diameter are these? 3mm?
 
4mm
sites usually state i.d. ..
....
i measured a silicon vac hose here ... i.d. measurement ..
before posting in this thread.

Brill - thanks, that’s what I was not sure about.
I’ll order up 4mm

Duh - I just re-read your first post - you told me 4mm id then! :oops:
 
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no worries .. easy to miss things sometimes .. :)
.
I was wondering is there no difference in vacuum produced, when the diameter is being changed on the hoses? The original seem to be 3.2mm and other 3.5mm or? At least that's what I found somewhere on a BMW site for the TD4.
 
I was wondering is there no difference in vacuum produced, when the diameter is being changed on the hoses? The original seem to be 3.2mm and other 3.5mm or? At least that's what I found somewhere on a BMW site for the TD4.

Well the 4mm id that I just got fits fine - never measured the original that closely. I just went with the advice on this site!
I would imagine that any difference produced between 3.5 and 4mm would be minuscule- but I’m no scientist!
 
The size of the internal diameter is irrelevant as far as the vacuum is concerned.
However the lines must fit snugly, or they'll potentially loose vacuum at the joints. BMW use 3.2mm ID pipe, which is very hard to find aftermarket. I've used 3.5mm which is fine, although that's not easy to get either.
 
i've had no issue with 4mm i.d. [secondary] hoses in mine.
i think the potential squashability of the vac hoses walls, is an important point.
hence i prefer the silicon ones, as opposed to cheaper non-braided rubber types.
..
 
The size of the internal diameter is irrelevant as far as the vacuum is concerned.
However the lines must fit snugly, or they'll potentially loose vacuum at the joints. BMW use 3.2mm ID pipe, which is very hard to find aftermarket. I've used 3.5mm which is fine, although that's not easy to get either.
Thanks Nodge68, https://www.ebay.co.uk/itm/25502705...6Ile0Nvt4juhG3Y9RQp7xo6y/Q==|tkp:BFBMkLn0_-Rh would those be ok, becaue those could be got as 3.2mm and 3.5mm or those https://www.ebay.co.uk/itm/40301168...qX/x73ihjvvpcX+5MDhUOev6Sg==|tkp:BFBMkLn0_-Rh
 

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