Power Steering low pressure hoses - substitutions?

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Kftca
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Location: NS

Power Steering low pressure hoses - substitutions?

Post by Kftca »

Hi all:
I am in the process of replacing the 4 low pressure power steering hoses on my 635. The correct hoses are metric size which are hard to find in my area. The question:
Has anyone successfully used SAE sized hoses instead without leaks? If so what sizes did you use?
The 4 hoses are:
16mm Id *. 22mm od (line from reservoir to ps pump)
12mm Id * 18 mm od ( line from steering box to reservoir)
8mm Id * ? Od (line from master cyl to reservoir)
6mm id * 12mm od (line from brake bomb to reservoir)

Any help greatly appreciated.

Thanks Karl
GRNSHRK
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Re: Power Steering low pressure hoses - substitutions?

Post by GRNSHRK »

I used 5/8" SAE sized hose on mine, series I with 2X lines to and from the reservoir, one to the pump and the other from the steering box, without any issues =D>

It was labeled 16.1 mm, just for reference :-"

Have you reached out to some of what I consider the "more reputable" sellers, like ECS Tuning, FCP Euro or turner Motorsport :-k

Just a thought, everything is on line these days \:D/
:mrgreen:
Bobbo
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Kftca
Posts: 15
Joined: Tue Nov 01, 2022 4:10 pm
Location: NS

Re: Power Steering low pressure hoses - substitutions?

Post by Kftca »

Thanks for the tip.
I was on the hunt for hoses today and got the same 5/8 inch SAE hose to go from the reservoir to the pump inlet.
I also got a 1/4 inch fuel line and a 5/16 in line to use for the 2 small lines (to the brake bomb and master cyl).
All these 3 lines look like they are going to work as they fit tightly on the hose fittings.

The problem one is the hose from the PS box to the reservoir which is 12mm ID. 1/2 inch (12.7mm) is too big. The good news is my local parts guy has found a supplier for this hose and I will have it in a couple of days.

I will report back when I get them all hooked up.


Karl
Kftca
Posts: 15
Joined: Tue Nov 01, 2022 4:10 pm
Location: NS

Re: Power Steering low pressure hoses - substitutions?

Post by Kftca »

Good day All:

I figured out the solution to this issue and thought I would report back to close the issue.


The 4 hoses are:
1) 16mm Id *. 22mm od (line from reservoir to ps pump)
2) 12mm Id * 18 mm od ( line from steering box to reservoir)
3) 8mm Id * ? Od (line from master cyl to reservoir)
4) 6mm id * 12mm od (line from brake bomb to reservoir)

For Item 1- you can use 5/8 ID hydraulic hose. Hose ID is 15.875mm Fits nice and tight. Warm it a bit or lube it with a bit of ATF, went on pretty easy.
For Item 2- There is no SAE equivalent that will work. 1/2 inch hydraulic hose is 12.7mm ID and is too loose. I did not try it but I thought it is sure to leak. I wound up buying this hose from an BMW aftermarket supplier.
For Item 3 you can use 5/16 inch fuel line (ID is 7.93mm) . Perfect fit.
For Item 4, you can use 1/4 inch fuel line (ID is 6.35mm) . A good fit as well.

Make sure you get the best clamps you can get that do not damage the hose and place them carefully just behind the shoulder on the nozzles.

I have no leaks which is really nice!!!

Thanks to all on the board.

Karl
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Sbeaud
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Location: Okahumpka, Florida USA

Re: Power Steering low pressure hoses - substitutions?

Post by Sbeaud »

A diagram that I found that may help visualize the hoses.
BMW 6 Series Brake and Steering Diagram.jpg
BMW 6 Series Brake and Steering Diagram.jpg (194.29 KiB) Viewed 1193 times
Scott
1988 M6
87Shark
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Re: Power Steering low pressure hoses - substitutions?

Post by 87Shark »

Someone PLEASE move this diagram to the tech section so it can always be found at a later date!!!!
'87 L6, Arctic White
GRNSHRK
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Re: Power Steering low pressure hoses - substitutions?

Post by GRNSHRK »

Agreed, Scott, thanks for posting =D>

Geez, what a complicated mess :roll:

I'll take care of moving it to the Tech Forum :-"
:mrgreen:
Bobbo
1980 633 CSi Cypress Green/Pearl Beige
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2005 330 Ci ZHP Cabrio Imola Red/Bone/Black
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Sbeaud
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Location: Okahumpka, Florida USA

Re: Power Steering low pressure hoses - substitutions?

Post by Sbeaud »

I found that diagram on one of the BMW forums a few years ago. I was ecstatic! Such a clear diagram. I think I asked on the forum the source and whether there were other system diagrams available, but I never got a response. :(

Scott
1988 M6
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