IIIPRO E4 4-Piston Hydraulic MTB Brakes - Are they to be trusted?

[Engikris]

These are probably the lightest 4 piston brakes on the market right now? I'm considering it for my incoming ultralight build.

[darkening]

I'm using these calipers with Shimano XT levers, and I'm happy so far(3 months of use). 4pot infront, 2pot rear. I use original BS05 shimano pads for rear brake and COOMA pink (ceramic) infront.

Resing BS05 pads bites earlier and have less modulation than pink cearamic. Overall, i think this calipers are good for XC. The levers are ergonomically and aesthetically bad, i dont like them at all.

[aeroskiii]

These are probably the lightest 4 piston brakes on the market right now? I'm considering it for my incoming ultralight build.

got mine down to 340g with 2 piston calipers. you can see if the trickstuff levers are compatible but they are pricey.

[Alexmenkov]

Hi guys. I just got these for my Ariel Rider x class and love them.
But the stock pads don't handle moisture very well, so I'm looking to replace them with something better.

Are there any brandname options available for these? And what's the best outlet to purchase from?

Tyia

[andrerav]

Hi guys. I just got these for my Ariel Rider x class and love them.
But the stock pads don't handle moisture very well, so I'm looking to replace them with something better.

Are there any brandname options available for these? And what's the best outlet to purchase from?

Tyia

Get these: https://vi.aliexpress.com/item/1005003821161271.html
The variant that fits your brakes is BP045. These are excellent in every way and are not phased by water. I use them on all my bikes.

[final forum]

Anyone who owns these brakes know if the newer IIIPRO IV4R 4 Piston Disc Hydraulic Brake, are any better or differernt?

Also i'm looking for better real estate on my left handlebar. Could I put my twinloc on the handlebar clamp or my dropper lever? Either that or going with a sram twistloc 3P remote. But that costs the same as these brakes. My Magura MT8 SL just seem so weak.

https://www.aliexpress.us/item/3256806171110649.html?spm=a2g0o.detail.pcDetailBottomMoreOtherSeller.2.2dcbBsR6BsR6uw&gps-id=pcDetailBottomMoreOtherSeller&scm=1007.40000.326746.0&scm_id=1007.40000.326746.0&scm-url=1007.40000.326746.0&pvid=64dfc9f3-c989-4372-a35a-7154f7583f0b&_t=gps-id:pcDetailBottomMoreOtherSeller,scm-url:1007.40000.326746.0,pvid:64dfc9f3-c989-4372-a35a-7154f7583f0b,tpp_buckets:668%232846%238110%23350&pdp_npi=4%40dis%21USD%2172.90%2156.13%21%21%2172.90%2156.13%21%40210330dd17278410195177751e5945%2112000036879659540%21rec%21US%21191630953%21X&utparam-url=scene%3ApcDetailBottomMoreOtherSeller%7Cquery_from%3A

[Tijoe]

Are They to be trusted?     To date, I have 3 sets in operation on different bikes.   Overall I have been pleased with their performance.   This being stated...

I recently finished riding a 600 mile bikepacking route that really put my loaded bike through the grinder.   You name it, I encountered severe riding conditions almost every day of the ride.   The brakes worked well until the last 2 days, I was having to pull the lever farther to get the same braking power.  I figured it was due to pad wear.

Yesterday I replaced the rear pads.  After replacing the pads, the lever pulled all the way to the bars without locking the calipers on the rotor while it is on the bike stand.
I removed the bleed screws, and set up my brake bleed kit, and went through my typical process that usually gets any bubbles out of the levers and calipers.  No improvement.  next I performed both a forward and reverse flush of the mineral oil.  No difference.   (I do this with the caliper removed from the frame, pads removed and the thick plastic spacer mounted between the 4 pistons.)

I am wondering why I can't get the brake to work again.  leakage across the brake lever piston?  Bubbles I can't get out of the caliper?   

Anyone else have this type of experience with these brakes?

[Tijoe]

This morning I swapped out my lever assembly and the caliper with a new IIIPro lever assembly and caliper. Purged fluid through the brake system, like I usually do.   New brakes purged quickly and has good lever response like it used to.

One item of note.  The new caliper I installed has a second purge port on the top of the caliper that my other IIIPro calipers does not exist.    I am wondering if they found out they have an air bubble removal problem in the calipers and added the second port.  (See attached images)

I am confident that I have a problem with the caliper.  I plugged the hose inlet and the lever built pressure when I pulled on it.   Then I installed the new lever and the problem persisted.  Swapped the caliper, bled the brake and all became good with great lever action.

What would cause the caliper to stop working after only a pad swap?   Despite trying all sorts of techniques to get bubbles out of the caliper, I was not able to get this brake to work.   I will have to take the caliper apart to determine it's problem.

[Tijoe]

Problem determined:   Per my previous post, I explained that I replaced my pads and no matter what I tried I could not get the rear brake to work, so I replaced the caliper and lever with a new one.

Today, I set up the old lever and caliper on the bench.  Upon careful observation of the caliper pistons, I see tiny bubbles of mineral oil coming out between the pistons and the caliper housing.  Looks like the seals have gone bad on 3 of the 4 pistons.   

Then I tested another caliper I removed in the past because it appeared to not be working.  Same problem! Little bubbles between the piston and caliper bores.

This is disconcerting because this means I have had caliper failures on 2 out of 8 calipers.   My first set was purchased and installed in early 2023.  When I look up the mileage since installing the IIIPro brake on several of my bikes, the distance ridden is perhaps 3K miles.   

Has anyone researched and ordered some sort of a rebuild kit?   (In preparation, I ordered a piston cap removal tool.)

I will write IIIPro soon ans ask about rebuild parts.  Bummer....

[nicklej]

I had similar issues. Bled mine multiple times after different ride intervals and they'd always start losing power to the point they were not functional. I don't know what options there are for a build kit but I replaced the brakes and maybe one day will look at servicing them again. I thought I had an issue because lots of riders sang their praises on these brakes but mine were always really weak. I'll stick with Shimano for now.

[Tijoe]

I am researching how to get new seals.   No reply from IIIPro on  what it takes to rebuild them.

I was able to remove 3 of the 4 pistons, without the cap removal tool.  (Ordered one off Aliexpress.)

As far as I can tell, these caliper are roughly cloned from Hope V4s.   
They have 16mm pistons. (15.9mm measured.)
They appear to require a 20mm OD x 16MM ID X 2mm wide  square O-ring.   No clue on durometer (hardness), or if they start out with some special shape feature, or if they are a regular square 2mm x 2mm square o-rings.

[Tijoe]

The Hope seals arrived this past Saturday.  This morning I installed 4 new HNBR red seals into the failed caliper and installed the pistons.   On the bench, bled new mineral oil through the lever and caliper.

After all of the bubbles were gone, I checked for firm lever action.  Fail!  The lever is still soft.  I took a look at the pistons and small bubbles of mineral oil are still coming out between the pistons around the seals.

Something simple like new seals didn't do the trick.  The new seals have the same dimensions as the old ones within the limits of my micrometer.  The pistons look brand new.  No indication of any wear on the surfaces.

Since they are still leaking, I am debating how much time to spend on finding what the problem is.  Time versus money tradeoff.   
Wondering if it is a housing o-ring groove tolerance machining issue, or if the pistons are undersized.   Who knows without spending a lot of time measuring and investigating all of the possible causes.   

Edit:  Since 2 of my calipers failed early in their life, and new seals didn't resolve the problem,  this indicates to me that it is a housing o-ring groove or piston diameter problem, or a combination of both.  (Part machining tolerance stack up?)

[jonathanf2]

Are you beyond your return period? I would have just sent them back for a refund. I bought an AliEx crankset awhile back, only to find out months later (when I was about to install it), the chainring screw holes aren't threaded! Now I can't return the crank which is completely useless.

[Tijoe]

Are you beyond your return period? I would have just sent them back for a refund. I bought an AliEx crankset awhile back, only to find out months later (when I was about to install it), the chainring screw holes aren't threaded! Now I can't return the crank which is completely useless.

Way past the return period...

2 of my 4 sets are over 1 year old. The third set is about 9 months old. I've had my 4th set for about 3 months, and had to put them in service because of the most recent caliper failure.

I have no way of knowing which brake calipers are on which bike because I often reconfigure my bike's components and swap front forks, or handlebars between bikes.  Therefore, all the front calipers are all mixed up between bikes, and to a lesser degree, the rear calipers.

[00Garza]

Are you beyond your return period? I would have just sent them back for a refund. I bought an AliEx crankset awhile back, only to find out months later (when I was about to install it), the chainring screw holes aren't threaded! Now I can't return the crank which is completely useless.

Yikes. What crank was that?