Pressure rod, rear master cylinder

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Dlg
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Pressure rod, rear master cylinder

Post by Dlg »

Is their a specific method of attaching the Pressure rod of the rear brake master cylinder into the master cylinder or is it just pressed in through the belows?
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Re: Pressure rod, rear master cylinder

Post by Our Gee »

Never had one to pieces but from other similar types I would say the pressure rod will have "ball end" which locates into a "cupped" piston without any form of mechanical attachment. (Similar to the Clutch Master Cylinder, which I have had apart) Parts diagrams (have a look at Max BMW Parts Fiche) show what looks like a bush located on the Rod ?. No doubt others with more knowledge will be alone to give more clarity.
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David.
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Re: Pressure rod, rear master cylinder

Post by David. »

Our Gee wrote:Parts diagrams (have a look at Max BMW Parts Fiche) show what looks like a bush located on the Rod.
The bush might be to locate the rubber boot (#3) on the rod (#2).

Image
Dlg
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Re: Pressure rod, rear master cylinder

Post by Dlg »

Attached is a picture of the pressure rod.
Am I right in thinking that the end just goes through the rubber boot and just rest against the master cylinder?
I don't see any mechanical attachment of the pressure rod to the master cylinder.


Attachments
20220310_081433.jpg
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David.
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Re: Pressure rod, rear master cylinder

Post by David. »

Having looked at the Haynes manual, I'd tend to agree with Our Gee. The manual shows two photos and describes the following, "disconnect the master cylinder pushrod from the brake pedal". One of the photos shows the master cylinder with the pushrod removed, the other with it in place.
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David.
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Re: Pressure rod, rear master cylinder

Post by David. »

Looking at the photo, it certainly appears that the pressure rod just locates in the master cylinder. The "bush" would seem to be the rod length adjuster nut.

Image

Image

The above photo would confirm that the pressure rod locates as described.
Last edited by David. on Thu Mar 10, 2022 8:09 am, edited 1 time in total.
Dlg
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Re: Pressure rod, rear master cylinder

Post by Dlg »

That's what I think.
It fell out when I took the whole right footrest and pedal assembly of to service my driveshaft.
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sakm
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Re: Pressure rod, rear master cylinder

Post by sakm »

They just sit in and not physically attached


Looking at the pics it looks like a Brembo master cylinder and they are known for using this sort of design
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Doctor T
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Re: Pressure rod, rear master cylinder

Post by Doctor T »

I can confirm that the rod just pushes through the rubber boot. Just put a smidge of grease on the rod before inserting it.
Trust me I am a retired Doctor and lecturer at Oxford University of Structural and Mechanical/Electrical engineering.
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