Replacing Pressure switch on brake pressure regulator

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Abdi
Posts: 7
Joined: Mon Dec 28, 2020 8:07 pm
Location: Texas

Replacing Pressure switch on brake pressure regulator

Post by Abdi »

Happy New Year everyone.
Need a little advice on taking off a leaking brake pressure switch.
I pumped lowered the pressure by pumping the brake pedal 20-30 times and observing the fluid level rise in the steering pump reservoir. Then I used a 24mm socket and tried to take the top switch off. But it appears not wanting to budge. I noticed that the whole regulator was trying to twist while I tried to take off the switch. So I stopped before I damaged anything.

Is this switch really this tight? Would I damage anything by putting too much force? Any advice on how to get this switch off is greatly appreciated
1981 320i
1986 635csi Japanese Spec
2000 M Coupe (aka, "Clown Shoe")
2005 X5
plip1953
Posts: 400
Joined: Mon Aug 13, 2018 4:15 pm
Location: Leeds

Re: Replacing Pressure switch on brake pressure regulator

Post by plip1953 »

Have you tried with an impact gun?
Phil
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1988 Highline 635 CSi
Abdi
Posts: 7
Joined: Mon Dec 28, 2020 8:07 pm
Location: Texas

Re: Replacing Pressure switch on brake pressure regulator

Post by Abdi »

Phil,
I don't have an impact wrench/gun so haven't tried. I could access one but I don't want to damage anything either by putting to much force manually or using an impact wrench.

Are these switches really on this tight?
1981 320i
1986 635csi Japanese Spec
2000 M Coupe (aka, "Clown Shoe")
2005 X5
plip1953
Posts: 400
Joined: Mon Aug 13, 2018 4:15 pm
Location: Leeds

Re: Replacing Pressure switch on brake pressure regulator

Post by plip1953 »

The point about using an impact gun is more about the way it applies the turning force rather than the amount of force, especially where what you're trying to remove is attached to something that itself isn't anchored especially rigidly. For example, it's perfectly feasible to remove a wheel bolt or nut when the wheel is suspended off the ground with now braking force applied - and you'd never achieve the same with a regular bar and socket.

But in terms of just how tight it is to start with, I honestly don't know, but wouldn't expect it to be much at all.

I assume it's 3 in the pic below that's the problem?
Attachments
635 brake accumulator.jpg
635 brake accumulator.jpg (26.43 KiB) Viewed 3791 times
Phil
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1988 Highline 635 CSi
Abdi
Posts: 7
Joined: Mon Dec 28, 2020 8:07 pm
Location: Texas

Re: Replacing Pressure switch on brake pressure regulator

Post by Abdi »

Phil,
Thank you for the information. It makes perfect sense. Yes it's number 3 on the diagram that is leaking. Although I am thinking I may as well replace number 2 also.

My concern about the use of impact wrench revolved around the potential to damage anything inside the pressure regulator ("voltage regulator" No. 1).

I will try the impact gun today. Thank you again
1981 320i
1986 635csi Japanese Spec
2000 M Coupe (aka, "Clown Shoe")
2005 X5
bpoliakoff
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Re: Replacing Pressure switch on brake pressure regulator

Post by bpoliakoff »

Many times when a bolt or nut is stuck, try to tighten it/"crack" it first which can break it loose
81 Euro 635 M90 with motronic. Currently under a complete nut and bolt restoration. Pictures at
flickr.com/photos/bertsphotos.
Abdi
Posts: 7
Joined: Mon Dec 28, 2020 8:07 pm
Location: Texas

Re: Replacing Pressure switch on brake pressure regulator

Post by Abdi »

A short pulse of impact wrench did the trick. Job done and no more nagging leak
1981 320i
1986 635csi Japanese Spec
2000 M Coupe (aka, "Clown Shoe")
2005 X5
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