Brake fluid....? Mushy brakes content

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Brake fluid....? Mushy brakes content

48 posts & 14 voices | Started 5 months ago by PeterPoddy | Latest reply from coffeeking

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PeterPoddy - Member

is the lever an assembly with the master cylinder or separate? Could it be flex in the lever/pivots?

Nope. New Master cylinder is the complete unit including lever.

Replace the caliper bolts first?

That's occoured to me too, but it'll be easier to pay £35 for a used caliper and bolt it on IMO, although I'll check them for tightness before I commit

This is really bugging me now. It's not a matter of money, becasue I can replace the entire brake (M/cly, hose, calliper, disc) for just over £200.... It's just that I NEED to know what the problem is!!!!

Posted 5 months ago #
bigyinn - Member

I completely understand PP.

I had a similar problem with a bike disc brake. Replaced the hose, hope, replaced the lever, nope. Turned out it was the caliper and one of the seals was letting fluid out / air in, but only slightly. Hopefully swapping the caliper out will fix it. Failing that I'd look again at the master cylinder.

Posted 5 months ago #
PeterPoddy - Member

Failing that I'd look again at the master cylinder

As above (somewhere) the M/cyl is brand spanking new.....

Posted 5 months ago #
singlespeedstu - Member

Replace the hose and calper.

Triggers new brake innit.

Posted 5 months ago #
specialknees - Member

Flexi Hose would be my last resort if it has one that is.

I had it on my Honda years ago, was de-laminating inside and causing the hose to expand. Didnt notice because it was hidden inside the stainless braid.
Once I replaced it and cut off the covering it was obvious.

Worth a try.

Posted 5 months ago #
PeterPoddy - Member

Well, a good condition used calliper didn't fix it.

And Venhill say that braided hoses don't degrade. But I'm not sure I believe them to be perfectly honest.

Posted 4 months ago #
PeterPoddy - Member

double post

Posted 4 months ago #
anotherdeadhero - Member

Vespa = Italian

There is your answer. Enjoy.

(twice in one day for this pic )

Posted 4 months ago #
PeterPoddy - Member

Get stuffed ADH!

(FYI I imagine the 'Heng Tong' branded parts the brakes are made from are, ohh, possibly Taiwaneese or Korean....??? Long shot I know....)

Posted 4 months ago #
anotherdeadhero - Member

Posted 4 months ago #
PeterPoddy - Member

Well, I sent off to Venhill for a custom made hose (£32 delivered, bargain) and it was delivered today.

I just had the time to chuck it all randomly together and bleed, and, on a swift basic test, it seems to be fixed.

So it was the hose. I was right. (and that's TWICE I've been right today, a record I think!)

Which was my first thought, before Modern Vespa forum led me to replace the master cylinder (£45) and STW led me to replace the calliper (£38)
I'm not annoyed. Really I'm not.

But by fek that's the last time I listen to anybody else with anything mechanical!

(I'm gonna pull the old hose apart and have a look inside. The old calliper and M/cyl are OK and I'll sell them on.)

Posted 4 months ago #
coffeeking - Member

Which was my first thought, before Modern Vespa forum led me to replace the master cylinder (£45) and STW led me to replace the calliper (£38)

Well, you wouldn't listen to me and TJ
...

TJ is correct, old fluid will only give you mushyness when you overheat it. I suggest you've either bled it wrong or your braided hose has a problem. Weepy seals in either caliper or master cyl will be identifiable by a creep test - get a fairly strong elastic to hold the brake on, leave it a day or two and see if it's at the bar when you get back. If it is you have a leak, but it's unlikely to make it mushy.

Posted 4 months ago #
PeterPoddy - Member

Fair point CK, I'd not re-read the whole thread again and missed that, my mistake.

Posted 4 months ago #
coffeeking - Member

Damn, now I mentioned it on the other thread I look like a glory seeking arse. Self publicity fail.

Posted 4 months ago #