Magura HS33 install questions

[bigbloke]

Hi All,
Before someone suggests the blinkin' obvious:

* I have RTFM'd
* I have WTYV'd (Watched those YouTube videos) - specifically : https://www.youtube.com/watch?v=kJOD_9BwgAw

and there are still a couple of things that are not just clear about fitting HS33 brakes !
grateful for any knowledgeable insight please!

[QUESTION-1]

in the youtube video on the topic - circa 00:00:14 Herr Kastle says:

"Before adjusting the hydraulic system always turn the pad wear adjuster back completely"

and shows in the video, the nearside brake lever turning the screw thread anti-clockwise.

Well the *&^%$£ lever design is now different to the video! (The brake wear adjuster has turned 90 degrees) and
I've done the front brake (offside lever on my bike) first. So should I interpret Herr Kastle's use of "back" as:

"Wind the brake pads fully into the calipers"

or:

"Wind the brake pads fully onto the rim of the wheel"

or even perhaps:

"With the wheel removed wind the brake pads as far out of the calipers as the adjuster allows"

Please ?

[QUESTION-2]

The Brake booster has two holes where the fixing bolts go - and the bolt heads go straight through both of them

I notice one hole is ovalled and extended , the other is round , and there is only one washer with one brake and two with the other .

Do I surmise correctly (having as I said - RTFM'd and watched the youtube videos a number of times) that:

The ovalled hole is used with the washer on the Quick release side of the brake caliper

The perfectly round hole simply goes over the cheese head bolt end on the ficed caliper side

The extra washer in the second brake pack can be considered "a spare" .

[QUESTION-3]

I see the tubing install procedure is based upon an olive and cap approach like a modern sink tap in minature.

Again in the video on the subject (@00:00:53) Herr Kastle advises:

"Take special care holding onto the hose to prevent it spilling oil"

It looks as if he is kinking the hose rather than just blocking the end off with his thumb ? I would have thought that
was not in the best interests of the hose ? is it ok to use say a small spring loaded wood routing clamp to stop an oil leak ? or perhaps a
"bung" of bluetack over the end ? or even just stick my thumb over it and keep it raised above the level of the brake lever
to prevent it pouring out ?

The video makes no comment on bleeding the cylinders so I assume a certain amount of air in the pipework is acceptable ? Is this a valid assumption please ?

Many thanks in advance

Regards

BB

[Cyril Haearn]

RTFM
read the.. manual
Had to wikicheck that

[Brucey]

1) 'back' = away from rim

2) LATFPD...?



3) air in hydraulic systems is not acceptable. Nor is kinking hoses!

Needless to say if you are in any doubt about what you are doing, it might not be a bad idea to take the bike to an LBS where they like these brakes, and ask them to fit them for you. If the installation is defective in any way, duff brakes can cause a very nasty accident.

Hydraulic brakes can be set up wrongly in no end of different ways, such that they might appear to be OK but then fail to operate correctly when you really need them.

cheers

[Cyril Haearn]

Are they too complicated for the layperson?
What advantages do they have?

[bigbloke]

RTFM
read the.. manual
Had to wikicheck that

not past the Watershed yet so:

"Read that fine manual! "

Regards

BB

[bigbloke]

Thanks Brucey.

Im reasonably comfortable with plumbing hydraulics. But can see no obvious way to bleed the cylinders
(theres probably a video in German that covers it)

Whilst we have 3 or 4 LBS I tend to end up either online or in a neighbouring city
due to either service, quality or time to repair factors.

Went to our newest LBS looking for a new ride for my Son , whose just outgrown his 24" specialised
and whilst we weren't given bad advice I walked away feeling quite insulted. Salesman had a speech impediment
- he actually paused for breath!

Suffice to say we ended up 12 miles away with a significantly better bike for an 80 quid price hike and a free service in
6 weeks.

[bigbloke]

Thanks Brucey.

Im reasonably comfortable with plumbing hydraulics. But can see no obvious way to bleed the cylinders
(theres probably a video in German that covers it)

Whilst we have 3 or 4 LBS I tend to end up either online or in a neighbouring city
due to either service, quality or time to repair factors.

Went to our newest LBS looking for a new ride for my Son , whose just outgrown his 24" specialised
and whilst we weren't given bad advice I walked away feeling quite insulted. Salesman had a speech impediment
- he actually paused for breath!

Suffice to say we ended up 12 miles away with a significantly better bike for an 80 quid price hike and a free service in
6 weeks.

[Brucey]

a good way of bleeding the slave cylinders with any hydraulic brake is to set up the MC so that the reservoir is full and open (or a bleed reservoir is attached to it), and pump the MC until the slave pistons are out as far as is (safely) possible. Then orient the slave cylinder so that the hydraulic connections is/are uppermost, and (slowly, until you are certain that fluid won't spurt out of the MC) push the slave piston(s) back. Repeat if necessary.

Any air in the system will be forced through to the MC provided the displaced volume in the slave pistons exceeds that of the hoses. Because of the way the fluid from one slave piston loops through the other, it is possible for air to get pushed the wrong way if the bleeding is not yet complete in the far end of the system.

Alternatively the bleed screws may be removed at both ends of the system and a syringe used to displace fluid through the system e.g. from bottom to top (where a bleed reservoir of some kind is needed). Provided this is done with a degree of enthusiasm, air will be purged from the system even if you have to push it 'downhill' in some hose runs.

cheers

[hufty]

(1) As above when setting up you want to wind the pad wear adjuster "back" so that the pads are as far away from the rim as possible, then set the brakes up with 2mm clearance (IIRC). During normal use that gap will increase because the pads get thinner as you use them, you tweak the adjuster to get your 2mm gap back again. Similar to the barrel adjusters on cable brakes.

(2) The oval slot of the booster gets the washer, and the screw goes through both washer and booster to fix it to the brake assembly at the top. On the other side the circular hole just pops over the screw head after you've assembled it all. This set up is so that when you use the quick release to remove one side of the brakes (eg to drop the wheel out) you can bring the quick release side forwards. If the brake booster was fixed on both sides you wouldn't be able to do that.

(3) I agree no need to kink it just use your thumb. As long as you don't let it flap around and keep your end up the oil usually stays in there. If you're trimming it, put the nut and olive on first then trim second and get it assembled quick!

Just to say that setup is usually a bit fiddly and time consuming, especially if you've not done it before. But once it's done it's done. My method is to assemble everything with the pads more or less flat on the rims, then loosen the fixing bolts top and bottom on both sides just enough so that increasing pressure on the brake lever makes the cylinder assemblies first become properly parallel then start to push away until the required clearance is there. Then tighten everything up.

There's no reservoir on a HS33 so for bleeding you need two bleed adapters and two hoses. You need one syringe at least, eBay will provide, so you might as well get two as then you can then bleed back and forwards easily, which you can't do with other hydraulics. Longer hoses eg 12-18" make it a lot easier than short hoses imo. Large syringes also make life easier.

[hamster]

Agree totally with the above post. They require a bit of puzzling at first, once you have done it once all becomes clear. The great thing is that you never have to do it again - I have sets that have run 15 years with nothing more than new pads snapped in and the odd twirl of the adjusters.
Usually you can get away with an open cut end, cut with the ends taped to a board so they don't flick loose. Add a drop or two of fluid to the open top of the slave before fitting the hose tip to minimise trapped air.

It's always easiest I find to bleed upwards that way any bubbles go the way they want to, so add fluid at the blanking screw on the slave. I fit an old HP sauce bottle to the tube screwed in on the master to catch the overflow. Keep injecting fluid though until no bubbles, then a bit more to be certain. And remember, mineral oil not DoT fluid!