Lost Power On Rear Magura?

[Captain Scarlet]

Well I have had my rear Magura for a year now, brand new when I got it, original bleed, so problems what so ever.

Lately the TPA has been jamming up, and yesterday the wheel was jammed solid, and cannot be undone.

Throughout the course of riding yesterday, my brake lever blade gradually pulled back further and further, like the TPA is set to minus.

The slaves have not moved, they are in the same position as always, and there is no sign of a leak.

The actual TPA rod is fine, but has this problem occured because of the jam of the wheel on the rod?

Or is there another explanation for this?

Just want to know before I go out and buy some new bits.

The brake does feel like the TPA is all the way on minus, and still works (it just takes longer for the pad to contact the rim due to the amount of movement in the lever),

So can a TPA wheel jammed on the rod have the same effect as the TPA being on minus?

And like I say, this gradually settled in throughout the day.

Any input would be appreciated.

Thanks,

Tom

Edited December 24, 2007 by Fugley

[JonMack]

I don't really understand your post but I'd say do the following things...

Take your lever off and sort out the TPA

Bleed your brake

That should sort any problems out.

[The Riddlers]

Ive never had any probs with my hydro's on my bikes.....BUT coming from a car mechanics background....sounds like you got a split hose somewhere!

[Captain Scarlet]

Well put simply.

The lever short pull a little bit, for the brake to then lock.

But gradually through the course of yesterday, the lever pulled back further, requiring a longer pull for the brake to work.

And as I say, there is no leak in the hose.

I just want to know what problems people have had with their TPA's, and the result of that.

The TPA controls the controls the pad's distance from the rim in the event of wearing the pad, this is done by puttting more pressure on the fluid in the hose.

Which is why, when you rebleed or shorten the hose you put the TPA to the minus position to reduce/eliminate the pressure on the fluid.

So if the TPA is jammed, it may not have proper control of the pressure on the fluid, and over time create the same effect as turning the wheel to minus.

[chris slater]

I had the same problem yesterday. I just took the lever off put it in water pumped it till no air coming out then reconected

the hose to lever whilst underwater and it did the trick..

Just try it mate it should work

[JonMack]

When peoples TPAs break they usually just stop turning. There is no way that the TPA would have any effect on the lever movement if you don't touch it, it has to be a split hose, and you're not putting it simply at all you're using shit english.

"The lever short pull a little bit, for the brake to then lock."

That doesn't make any sense.

Right I can't even understand your post to be honest your english is shit.

"So if the TPA is jammed, it may not have proper control of the pressure on the fluid, and over time create the same effect as turning the wheel to minus."

Not true at all, if the TPA is jammed, then it's jammed, it doesn't move, it wont change the "pressure" of the fluid at all, it just jams.

If your TPA is staying in the same place for the WHOLE ride, and the lever is slowly needing to be pulled further, then you have a leak, end of story.

[dave85]

If this is a post-05 magura with the red TPA wheel within the lever blade, it is perfectly possible for it to strip the threads in the wheel, then for the pin to push its way down through the wheel, giving the effect you describe. Given no other damage, a new TPA is all that is needed.

[Alex-Mitchinson]

Seen as your TPA won't turn I would say that the thread on either that or the pin is stripped. If the thread is stripped then this might mean that the pin will move without the use of the TPA wheel because it can't lock into the threads properly.

EDIT: Dave85 beat me to it.

Edited December 24, 2007 by alex jersey

[JonMack]

Here's some corrections.

Well I have had my rear Magura for a year now, brand new when I got it, original bleed, so problems what so ever.

Lately the TPA has been jamming up, and yesterday the wheel was jammed solid and couldn't be undone. Throughout the course of riding yesterday, my brake lever blade gradually pulled back further and further, like the TPA is being loosened. The slaves have not moved, they are in the same position as always, and there is no sign of a leak.

The actual TPA rod is fine, but has this problem occured because the wheel is jammed on the rod, or is there another explanation for this?

Just want to know before I go out and buy some new bits.

The brake does feel like the TPA is unscrewed all the way, and still works (it just takes longer for the pad to contact the rim due to the amount of movement in the lever), so can a TPA wheel jammed on the rod have the same effect as the TPA being unscrewed?

Like I said, this gradually settled in throughout the day.

Any input would be appreciated.

Thanks,

Tom

Well put simply.

The lever pull was short for a little bit for the brake to lock, but gradually through the course of yesterday, the lever pulled back further, requiring a longer pull for the brake to work.

As I say, there is no leak in the hose, I just want to know what problems people have had with their TPA's, and the result of that.

The TPA contols the pad's distance from the rim in the event of wearing the pad, this is done by screwing the piston further into the cylinder which then pushes the pads closer to the rim which is why when you rebleed or shorten the hose you put the TPA to the minus position to reset the position of the piston.

If the TPA is jammed, it will not have proper control of the piston.

Nothing to do with pressure, all the TPA does is screw the piston further into the master cylinder to push the pads closer to the rim.

EDIT: I also assume it's a post '05 Magura as you said you've had it a year and bought it brand new.

Edited December 24, 2007 by JonMack

[Captain Scarlet]

Jon your being a bit hypocritical aren't you?

Right I can't even understand your post to be honest your english is shit.

With your corrections.

The lever pull was short for a little bit for the brake to lock

Your correction doesn't make any sense?

The sentence I put was merely a typo and the word "short", was supposed to be "should".

Thanks Dave85 and Alex, upon checking it appears that the threads on the wheel have been stripped, so the pin slips as a result of this.

As a bodge, I have packed out the section of the lever, just under the threaded part of the pin, with some cut up zip ties.

I should be getting a new TPA kit when Tarty re-opens.

Thanks again.

Edited December 24, 2007 by Fugley

[JoeM]

Jon your being a bit hypocritical aren't you?

With your corrections.

Your correction doesn't make any sense?

The sentence I put was merely a typo and the word "short", was supposed to be "should".

Thanks Dave85 and Alex, upon checking it appears that the threads on the wheel have been stripped, so the pin slips as a result of this.

As a bodge, I have packed out the section of the lever, just under the threaded part of the pin, with some cut up zip ties.

I should be getting a new TPA kit when Tarty re-opens.

Thanks again.

This is exactly what happened to my brake. It turned out to be a leak, so what I'd do is wack some new hose on, bleed it and see if that does anything. If it doesn't do anything then you've got a leak in your leavers or pistons. Just try that for the time being.

Edit: Sorry i pressed reply on somebody else's post . I meant to reply to the main post.

Edited December 24, 2007 by Joeee

[Guest]

I should read posts more carefully...

Edited December 24, 2007 by Jakers

[Ryan Blackwell]

You know what i think tom STONE IT.

[Balman]

if it were me id just rebleed seems to solve everything ha and on then new maguras the tpa normally jams really easy mine did with in a few days so i tend to go for the older ones personaly but yeah try rebleeding and flushing out the system

[sidehop]

You've stripped you TPA mate, i ust to do it all the time but i got a 04 again.

BUT what you need to do it buy a new TPA get a metal one and you will be reeet for years.

Chizz...

[Charlie Jennings]

Drill your tuppa out.

Pull the fooker out

Fi the new one. simple.

[Alex-Mitchinson]

Drill your tuppa out.

Pull the fooker out

Fi the new one. simple.

What fantastic use of language you used.

But, lets ignore it and stay happy, merry christmas to all.

Edited December 25, 2007 by alex jersey

[Captain Scarlet]

Drill your tuppa out.

I've already got the TPA out.

How else did I find out that the threads were stripped.

TPA kit, Hen bikes wheel, and Echo Lever

NYCE!

[sidehop]

I've already got the TPA out.

How else did I find out that the threads were stripped.

TPA kit, Hen bikes wheel, and Echo Lever

NYCE!

Owned by Mr F.

Also that will sort your problems out mate.