Master cylinder.

Discuss mechanical problems here.
Forum rules
By using this site, you agree to our rules. Please see: Terms of Use
Post Reply
The Black Baron
Minor Friendly
Posts: 57
Joined: Tue Feb 17, 2015 9:58 pm
MMOC Member: No

Master cylinder.

Post by The Black Baron »

Hi all,

Just filling up fluids tonight. Went to fill up the brakes, and fluid pouring out the chassis from around the master cylinder.

Took the cylinder out, Andy the fluid is pouring out of this little hole (upper left). Anybody seen this before, as we don't know why its there. Maybe missing a blank or something? It's thrown us.



Cheers,

David.
Attachments
IMG_2125.JPG
IMG_2125.JPG (1.01 MiB) Viewed 3000 times
les
Minor Maniac
Posts: 8737
Joined: Tue Feb 12, 2002 12:00 am
Location: kent
MMOC Member: Yes

Re: Master cylinder.

Post by les »

Never seen a hole like that in a cylinder before, I presume it's a replacement. Where did you get it from?

BLOWNMM
Minor Fan
Posts: 281
Joined: Tue Dec 09, 2014 6:14 am
Location: Australia
MMOC Member: No

Re: Master cylinder.

Post by BLOWNMM »

Definately should not be there !!??
Bob
Image
Trickydicky
Minor Legend
Posts: 1565
Joined: Fri Aug 05, 2011 9:53 pm
Location: Leeds, West Yorkshire
MMOC Member: No

Re: Master cylinder.

Post by Trickydicky »

Is there a hole in the chassis leg in the same position? It looks like someone has drilled a hole in the chassis leg and and gone straight through to me.
Richard

Opinions are like people,everyone can be different.
BLOWNMM
Minor Fan
Posts: 281
Joined: Tue Dec 09, 2014 6:14 am
Location: Australia
MMOC Member: No

Re: Master cylinder.

Post by BLOWNMM »

The hole is in a curved section towards the top. I thought a drill bit would have tended to run off a bit and not produce such a clean neat hole without ragged edges as the pic shows.
Bob
Image
RobThomas
Minor Legend
Posts: 2646
Joined: Thu May 11, 2006 10:34 am
Location: Cardiff
MMOC Member: Yes

Re: Master cylinder.

Post by RobThomas »

Is the hose at the back a clue? Looks like a remote reservoir.

The hole would be the right height for an overflow but you'd need a reservoir to be at the same height. Is there another filler somewhere?
Cardiff, UK
BLOWNMM
Minor Fan
Posts: 281
Joined: Tue Dec 09, 2014 6:14 am
Location: Australia
MMOC Member: No

Re: Master cylinder.

Post by BLOWNMM »

It certainly looks like a remote filler hose at the rear however why would you need an overflow? I have a remote reservoir installed on my MM and it does not have an overflow nor does it need one. Seems something of a mystery.
Bob
Image
oliver90owner
Minor Legend
Posts: 1653
Joined: Thu May 12, 2016 6:33 am
MMOC Member: No

Re: Master cylinder.

Post by oliver90owner »

I thought a drill bit would have tended to run off a bit and not produce such a clean neat hole without ragged edges as the pic shows.

Easy to do - just use a rigid cutter, like an end mill. OP needs to seal up the hole and carry on. Having ascertained that clearly it is not a standard attribute, remove it or replace the whole M/C.
Declan_Burns
Minor Legend
Posts: 1956
Joined: Wed Apr 18, 2007 7:32 am
Location: Düsseldorf, Germany
MMOC Member: No

Re: Master cylinder.

Post by Declan_Burns »

There could be still some swarf inside the M/C. I would remove it and flush it out just to be on the safe side or replace it for peace of mind.
Regards
Declan


Regards
Declan
BLOWNMM
Minor Fan
Posts: 281
Joined: Tue Dec 09, 2014 6:14 am
Location: Australia
MMOC Member: No

Re: Master cylinder.

Post by BLOWNMM »

Oliver - see my post at 4:04 pm.
Bob
Image
les
Minor Maniac
Posts: 8737
Joined: Tue Feb 12, 2002 12:00 am
Location: kent
MMOC Member: Yes

Re: Master cylinder.

Post by les »

Yes there would be a run off if a drill hit the cylinder, rather than a clean hole.

The Black Baron
Minor Friendly
Posts: 57
Joined: Tue Feb 17, 2015 9:58 pm
MMOC Member: No

Re: Master cylinder.

Post by The Black Baron »

Yeah, its a perfectly smooth hole. There are no holes in the chassis and definitely not a drill hole for sure. It's too good.

Remote reservoir pipe at rear indeed, goes underneath and into engine bay.

Don't know where we got this one from- we did start the project over 20 years ago, so much has been forgotten.

New cylinder or weld up then!

David.
philthehill
Minor Maniac
Posts: 10767
Joined: Thu Jul 19, 2012 12:05 pm
Location: Hampshire
MMOC Member: Yes

Re: Master cylinder.

Post by philthehill »

'New cylinder or weld up' - I would do neither.

Blind tap (not all the way through using a second or No: 2 tap) the hole and fit a short grub screw using Loctite Loc & Seal so as to ensure a complete seal.
Greasing the tap will catch most if not all of the tapping swarf - but as advised above clean out the inside of the cylinder.

firedrake1942
Minor Legend
Posts: 2942
Joined: Tue Aug 25, 2015 6:07 pm
MMOC Member: No

Re: Master cylinder.

Post by firedrake1942 »

Were the brakes working before you did your fill up ? I can't really see how if there is a leak for the MC.
philthehill
Minor Maniac
Posts: 10767
Joined: Thu Jul 19, 2012 12:05 pm
Location: Hampshire
MMOC Member: Yes

Re: Master cylinder.

Post by philthehill »

There would be no reason for the master cylinder not to work as it should as the hole duplicates the vented cap normally fitted; and as the hole is at the top of the cylinder there would still be fluid contained within the cylinder body as normal so that when the pedal was depressed the brakes would operate as normal.
If the hole was at the bottom of the master cylinder it would be different as the brake fluid would drain out and there would be no brake.
I would suggest that who ever fitted the master cylinder and what appears to be a remote reservoir has read the fitting instructions wrongly, fitted non vented caps to the remote reservoir and master cylinder and to overcome the lack of brake fluid entering the body of the master cylinder drilled the hole to vent the master cylinder.
There is no sane reason that the hole should be drilled so the above may be so fanciful to be true - but who knows.

The Black Baron
Minor Friendly
Posts: 57
Joined: Tue Feb 17, 2015 9:58 pm
MMOC Member: No

Re: Master cylinder.

Post by The Black Baron »

philthehill, I can answer that having had it all apart and been underneath it for far too long!

It was a drill bit through the chassis for a securing clip that went a ‘little too far’!

The remote reservoir is vented and works fine. I will post a quick update in restorations. :)
simmitc
Moderator
Moderator
Posts: 4718
Joined: Thu Apr 15, 2004 9:43 am
Location: Essex
MMOC Member: Yes

Re: Master cylinder.

Post by simmitc »

13th June 14:36 "Yeah, its a perfectly smooth hole. There are no holes in the chassis and definitely not a drill hole for sure. It's too good."

22nd August 20:03 "It was a drill bit through the chassis for a securing clip that went a ‘little too far’!"

I'm glad that's cleared up :roll:
Post Reply