Nerding out on Brakes shall we? Not another tech deraliment

The hope love has really started to come out here. I'm probably going to get them next, messed with some tech 4 v4s braided hose the other day and really liked the way they feel, super smooth but positive enough on the bite. 

Can I come into this thread with a question? I would like to attempt my first brake bleed (ever) on a Shimano Saint, since it seems a little inconsistent. The rear brake gets weird sometimes, where I have to throw the lever in quick succession a few times because the contact point is suddenly right in the beginning of the stroke and it feels wooden (that means air in the system, right?).

Bought that AliExpress bleed kit after it received some high praise in the Tech Rumours thread. But now I'm trying to figure out which oil to get. Standard choice seems to be Shimano SM-DB-OIL, but I randomly found a reddit thread where they recommend lower viscosity oil, Redline Likewater in particular.

So, which one should I get (and why) and how much of it? Assuming the standard Shimano stuff is in there, do I need to flush everything out if I want to try a different option?

Also, do I go lever bleed or gravity bleed?

Bonus question: my brand new XT brakes (the now older model, but came on a new bike and were ridden like 10 times by now) had a wandering bite point in the rear pretty much from the beginning. Do I even bother trying to fix it? Seems to be a hopeless endeavor from what I've read.

Bonus question 2: I just remembered that some bike shop person in Whistler claimed to have broken brakes while trying to bleed them?! If that's an actual risk, is it more like 0,5 % or 50 %?

Do it. I've just upgraded my old T3 V4 braided line pair on the DH rig to T4 levers and oh boy, what a neat and relatively inexpensive upgrade.

My recommedation is to go for LikeWater or Putolines HPX R 2.5 fork oil. Both help massively with the wandering bite point issue and are better if you ride at colder temps.

Gravity bleed and lever bleed after it is good, I’ve always used a shimano cup at the lever and a syringe at the caliper. 

Yeah you need to flush the all of the old brake fluid out if you change fluids.

I guess its possible to somehow break your brakes while bleeding but highly unlikely, its an really easy process, especially with Shimano. 

Since I saw this one 7 years ago this is how I've bled all my shimano and it has always worked well. I use putoline 2.5W but used to use the normal shimano.

Breaking Shimano brakes during a bleed is easy. You just have to apply pressure to the system, this pushes on the membrane which is then pushed against a pin in the cover of the membrane on the lever. Same issue if you have air in the system and go on a plane.

Its very easy to damage it if you don't know what to look for. 

I've had alot of trouble with my Shimano xt brakes- the first set of brakes I've worked on myself. But after a while I've now got them working reasonably well. I'll probably buy the new hope brakes in the next year. A few tips anyway-

- The syndicate bleed guide above is good but I've also always had to do a lever bleed on top of that, with the pads and rotors installed, in order to get acceptable levels of free stroke.

- There are 2 ways in which you can fairly easily break them. The first is by over pressurising the system, IE pushing the pistons back in without a bleed funnel. This can unseat or even puncture a rubber diaphragm inside the lever assembly. This will present as oil leaking out of the end of the lever, and can be fixed quite easily by either repairing the puncture or reseating the diaphragm. The second way they can break is the pistons can crack as they're made of ceramics. You can minimise the chances of this by buying the correct bleed block, but I think they can still crack if you're unlucky.

- I've had to lube and exercise the pistons to get them moving properly. Walk them out (not all the way out), lube with mineral oil and get them moving in unison before cleaning.

What Ali express bleed kit are you using that you've seen recommended?

Thanks everyone, the replies have already been super helpful! Although I'll admit the task seems as daunting as ever.

This is the AliEx kit (gotta switch to your country), bought the 2022 STD variant (box with 10 different connector pieces or whatever they're called). Someone in the Tech Rumors thread even claimed to have seen it used in the DH World Cup pits.

The point with the lever bleed for free throw is interesting! Would that also apply to other brakes? Derailing my own question here, but I've parking lot tested my friends Dominions. Based on reviews alone, I thought they are exactly what I want (super light lever, lots of modulation, strong power), but they feel terrible to me: extremely strong but bite to almost full power within the first 3 mm of lever pull. 

So far, my favorites from lever pull have been Hopes, but the lever shape was terrible for my taste. New version seems to mitigate this though, so if I'm ever in the market for new brakes, it's gonne be those (or Maven Base if I find them for super cheap). Anyway, I've been surprisingly happy with the Saints. It was a bit disappointing to get something this "old" on my latest purchase, but so far they do everything I want quite well.

if you want light lever pull, get the intend

I was about to sass you about them never being in stock, but they actually have some available at this moment in time!

Trinity 2.0 black & silver - Intend

Finally got hold of a set of GR4s after years on the Tech 4 V4. As with all things Hope the build quality is a work of art. First impressions:

I bled the ‘old’ way without using the bleed port because I didn’t have the adapter for the funnel yet .Hopes new bleed video gives a few new steps which seem to work good.

Lever is a touch heavier throw than the v4 but much shorter throw before bite due to the new cam design. It’s still very light. 

Extra hook on the lever is really nice, way more secure 

Bigger piston is noticeable in the power increase, not huge on the v4. 

Still a lot of feel at the lever which is my favourite thing about the hopes compared to the mavens or Shimano that have that on/off. Just preference.

Love they share the same pads and some hardware so all my T4 spares are not useless!

This guy always does interesting combos. I dig it

I noticed yesterday that I've managed to kink my rear brake hose on my DHR Evos in 2 places - one at the junction into the head tube (from swapping forks out..) and the other at the entrance to the levers (from my light pushing it in that place).

Never had hoses kink before, could it be that the TRP hoses are softer than anything else (ie Formula and SRAM)? Could I be losing power from the flex?

I'm a little late for this to be news, but I'll post anyway.

After 2.5 years of use I had an issue with the Code RSC brakes. It's going to need a new lever body, I'll replace it and throw them on my spare bike. 

I installed the set of Hayes Dominion A4s that I had been planning to install on the spare bike, but hadn't gotten around to. 

A few quick observations.

The Hayes are easy to get a good bleed on but the process is messy. It's almost the opposite of the bleeding edge system, which is a little more difficult to get a perfect bleed but is very clean. It's a mild pain that Hayes only includes one barb and olive, I originally left my front hose a bit too long and had to wait until more arrived to shorten the hose. Aligning the calipers was easy with the grub screws. 

The brakes feel good, and are quick to get used to. The initial bite is similar to Codes but power ramps up faster more like Shimano.

Can’t answer the question about the hose softness, but wanted to chime in and say it’s unlikely that the kinked lines are causing any power issues. I’ve ridden with some pretty severe kinks with no problems…

Does anyone run smaller rotors in the cold (freezing plus or minus 10-15F) weather to try to keep them working better? Specifically for all-mountain, enduro or whatever we call it these days type of riding. 

I do a lot of enduro fat biking in those temps and run 200/180 rotors. Runs are between 300-500M of elevation drop. Anything smaller wasn't cutting it and anything bigger was too much. On my summer bike and same trails I run 220/200. I also run Sinter green pads so the initial bite is not too dependent on how much heat you have in the system. So to your question, yes downsize. 

No I haven't, thought about it, but just didn't bother, no issues using 203's in freezing temperatures.

I have had this happen on my SRAM setup where the kink was bad enough to cause brake loss. The plastic tube in the brake hose kinked at the sharp head tube routing exit and starting leaking fluid in the housing. Kinda like a pinch flat within the hose. No external fluid loss but enough to cause pressure loss in the system. Some frames like speciazlied have a sharp exit port which I now sand a little bit to make it smoother. Kevlar lined hoses are more resilient because when the same happened to my Intend hose it kept working just fine. YMMV but the general rule of thumb is to replace it.

Funny enough, I trimmed and bled a pal's Elixir for brake issues this weekend (yes, we talked about how updating the brakes would be a good idea). Anyway, the brake with the kinked hose was working-ish. The kink was bad enough to cause a fluid restriction, so the pistons wouldn't return the way they're supposed to. This of course meant a real short lever stroke and pad rubbing.  Nipped the hose down a smidge, new comp bushing and bled and the brake feels fine. Power wasn't an issue, just brake functionality. His was bad enough that I didn't feel 'rounding" the hose back into shape was a valid repair option. If yours isn't terrible, you can give that a go with a set of needle nose pliers. Easy does it, don't go ham fisting the job. I've done it numerous times back in my industry days. When companies were still figuring out how best to run hydro lines there were numerous kinked brake line issues we addressed in the field. Some just needed to be rounded out again and rerouted, but sometimes they were bad enough to cause internal failures. Those were a hoot for everyone involved.

TRP made a running change to the hoses, they added a stiff plastic liner.  I didn’t know about this when installing my Pros and kinked it twice.  Ran it the entire season like that and didn’t have any issues.  Apparently the soft hoses were causing the soft bite point.

when did they make this change?
Quite a few people run the Saint hose still.

Following on from the Shimano/TRP hose question - has anyone used Shimano barb/olives? The only supplier that will deliver to me for TRP barbs and olives wants £20 just for shipping!

Use the TRP barb/olive on the Shimano hose.  Works great, it just a weeee bit snug slipping the olive on the hose, but it works.  

I have early run Pros, so those probably shipped with them from the get go.  I have a set of the DHR Evos with the updated lever adjustment from early 2024 and those still have the old hose.

This is interesting - I received a set of GR’s and they had the bucket adapter in one box.

Cyclocross wrenching background - rather than smaller, we found pads that heat up faster are better. The alloy core rotors manage high temp better but also get up to operating temp faster.

Now have 2 sets of 6 month old T4 V4's that have horrendous amounts of wandering bite point, gets slightly better after a bleed but immediately returns after 200m of descending. No visible leaks and no pad contamination, very odd. At first, I was thinking either the diaphragm or master cylinder piston, but I'm almost wondering if it has something to do with seal rollback on the caliper pistons (ie not retracting fast enough), as it doesn't seem to be ingesting air. Has anyone else had similar problems?

I did have a master cylinder on a V4 that did something this.

It would be fine in the garage and feel spongy on the trail at times, then Ok - very inconsistent.

After a ride I would check things - no leaks, top off fluid at the MC, bleed, and it would help for a bit and then boom - same deal.

Contacted Hope and they recommended swapping out the diaphragm seal as a first troubleshooting step and has been problem free since.

Updating post to add that the diaphragm that was removed didn't have any obvious physical defects - no holes, no chunks missing, etc. I did not run tests to figure out where the diaphragm was leaking.