Damaged bleed nipples?
 

Hi all,

I'm hoping someone has experienced something similar to the following and can offer some advice.

I fitted some Goodridge stainless braided hoses to my SV a couple of weeks ago. After the usual bleeding procedure with took a good while, I cable tied the front brake lever to the bar overnight and had a good feel in the lever for a while.

However after a few days I noticed the lever was coming back further toward the bars... I bled at the calipers again and got a bit of air out. Same thing happened a few days later... but this time when i took the rubber cap off the nipples there was a bit of fluid in them (the nipples were done up tight).

Is there a seal in the bleed nipple assembly which could have gone? Or could it be the thread has been stripped slightly?

Thanks for reading,

Rick

No there's isn't a seal, it's metal to metal, it shouldn't be that tight the torque setting is 5lb-ft, ie, not much.

Don't be surprised if there's a bit of fluid in the tube of the nipple, it's about an inch long in total, and mostly upright, so a little fluid will lay in it when you're done bleeding. After bleeding I sometimes use a bit of workshop paper, like kitchen paper, to soak the fluid out of the nipple, and then put the tube of the WD tin in there and give it a little squirt, cover with rag whilst doing so else it'll spray all over, I find this helps reduce corrosion of the nipple, and problems undoing it in the future.

Thanks for the tip,

I am just a little worried as i'm bleeding the brakes until there is no air left and then a couple of days later I have air in both calipers again. I've checked the rest of the system and there are definitely no leaks anywhere. The feel at the lever was stiffer before i upgraded the hoses i think!

Its also possible that I could have over tightened the nipple it in an attempt to stop it leaking. I assume if I have done that I may have damaged the thread in the caliper which would mean new calipers right? :-(

Possibly... I can probably find a couple of spare nipples if you want to try and swap them over. they'll be ugly, but should work... Is it possible that you have a leak at the piston seals?

Re: Damaged bleed nipples?
 

What have you been doing :shock:

When i fitted the new brake lines i completely overhauled the calipers - clean up the pistons, and fitted both new fluid and dust seals. I'm sure there is no leak there but I will take the calipers off again this weekend to make sure.

I've noticed you can buy stainless bleed nipples for about £4 each so I will probably just get some and see if it helps.

How long do you guys go without getting air in the calipers? Months? For ever?

Once the system is proerly bled, there will be no air in it at all and no need to bleed until the system is next disturbed.
The trick is getting all of the air out, and also very often the air in the fluid on filling is in many microscopic amounts, and there are no bubbles as such to remove, this why you when bleed the system, there seem to be no bubbles coming out, but the lever is still not fully up to pressure, some time later, the air has coalesced and then there are more proper bubbles to get out.

If your bleeding technique isn't perfect, or sometimes with a particularly troublesome system, the best thing to do is to remove the entire system and arrange it on the bench with all the hoses going uphill from the M/cyl, and the cailpers arranged such that the bleeds are fully uppermost, bleeding this way, and agitating the system to dislodge any trapped bubbles, can sometimes be the only practical way to get it bled completely.

If that was all that was happening, wouldn't he have a soft lever from the start, instead of losing pressure over time? That definately implies a leak to me...

my nipples where damaged the other day.. but thats another story... :roll:

I was thinking of getting some of these http://cgi.ebay.co.uk/ws/eBayISAPI.d...sPageName=WDVW

I have deffinetly suffered from the spongines after refilling the system with brand new fluid and bled and bled and swore and bled some more but still no bubbles. It went for a service about a month after came back perfect and has been fine ever since.

Has anyone used the motrax little bleeder? is it any good or does it just do the same job as a piece of tube and a bottle from halfords?