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babalegba

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So, you didn't mention but:
1- I assume you greased those pins before reinserting, yes? They shouldn't go in clean. In fact, most of the (hopeful) hypothesizing around why there's uneven wear (because uneven brake wear is NOT normal on a floating caliper system) is due to the pins not being greased properly during assembly.

2- Where's the brake booster reservoir to pop the cap? I assume you had to re-compress the pistons to fit the thicker/new brake pads

3- Do you have a solution/plan for releasing the rear brakes? On my Volvo, we were able to use a 9V battery and some alligator clips on the harness to 'release' the parking brake. I'm not sure how this might be achieved unless the Rivian system is the same since we won't have access to the software tools to put the vehicle in 'brake change' mode or whatever they use...

That said, I'm at 36k miles and just rotated my tires. There's albeit 0 wear on my pads to date. They're thiccc and symmetrical. At least so far! I'm sincerely betting I'll get well over 100k before I need new ones, unless something goes sideways.
Good points. I didnt intend this to be a detailed how-to, my intent was to highlight any key findings.

1- Correct, Both pins were greased after cleaning with a wire wheel. There is also a larger center pin but the pads do not slide on it. That was also greased nonetheless.

2- I believe it is in the hood area next to the cabin filter section. I believe i saw it a while back while changing the filter. I didnt open it up for this maintenance though. I also did push back the pistons to reinsert new pads - that pressure would have gone to other wheels.

3- My assumption is that the "park brake release" option below should take care of it? FYI i used the "tire change" option for my brake pad replacement. Not sure if that deactivates any suspension movements though. Good point. Will ask the service advisor during my upcoming scheduled appointment for some other things.
Rivian R1T R1S Brake Pad Replacement DIY for Rivian R1 IMG_0291
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I have can not wait for someone to come out with a carbon ceramic brake kit. Not so much for the braking performance but to ditch something like 10-15 lbs off each corner of unsprung rotational mass would do wonders for the dynamics and especially ride quality (less unsprung weight lets the wheels move faster to soften bumps and keep the wheel on the ground).
This plus lighter wheels and tires, and I’m curious what sort of efficiency could be accomplished!
 
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I sent you a DM, but figured I'd ask here too. Are those 275/60's? If so, do you have more pictures? I'm looking to do a similar setup
They sure are! DM replied with pics.
 

Luvolbikes

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Agree the Harbor freight badlands offroad Jack is the best. I just bought one and already used it doing a rack and pinion replacement on my old Ice car. That along with the 12 ton HF Jack stands, a pair of rear drive up ramps and some smaller stands gave me easy high working room beneath the car and peace of mind that the car would not fall on me..
I am also a DIYer but acknowledge the R1t will limit my DIY interventions other than resets and nut and bolt matters. I'm surprised you had brake wear issues that soon. Something wrong there. Regenerative braking should slow brake wear and usually increase tire wear. My f250 super duty got around 100k on it's brakes and that was often pulling 10,000-12,000 lb trailers up mountains at times. Trailer brakes helped of course.
I would love to hear what Rivian has to say about early brake wear. They have been less than forthcoming with answers on other mechanical questions I have asked them. Better answers on this forum.
For a DIYer $800 is outrageous for even a 4 wheel brake job including rotors, pads. I expect less than $200 dollars in parts from anyone but Rivian or dealers in general.
Thanks for the excellent write up. I'll do my own when the time comes. Might be a good idea to check wear on a regular basis and practice preventative maintenance when possible.
 

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Nice write up - thank you.

Do you have the regen brake assist activated in the software? Odd that it wore through the inner pad - something was sticking.

Don’t forget to go out and bed in those new pads to ensure they mate with the old rotors. I’d do about 10 hard brake applications (hard but don’t engage ABS) from 60-20 mph in low regen. Don’t stop while the rotors are hot, and be mindful of traffic!
Thank you - i did that this morning on my way back from the gym. Sunday morning at 7am on a side road seems perfect for this! Brakes definitely grippier now, so that previous gunk buildup was def affecting performance. I also had high regen, which uses friction brakes (i believe).


Great write up, and helpful tips in the comments. Thanks for this.

One question: for the rotors, can you tell if they're bolted on or otherwise any difficulty in removing once the calipers are out of the way? My previous truck, the rotors were hydraulic-pressed onto the hubs. Dumbest design ever. It was pretty common for people to just beat them off with a sledge. Any sign of similar issues here? Ty!
There is a black screw in the pic below. From similar rotor replacements in the past, i believe this just needs to be backed out, and a good ol mallet should complete the job. I dont foresee any issues.

Rivian R1T R1S Brake Pad Replacement DIY for Rivian R1 IMG_0259
 

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Thank you - i did that this morning on my way back from the gym. Sunday morning at 7am on a side road seems perfect for this! Brakes definitely grippier now, so that previous gunk buildup was def affecting performance. I also had high regen, which uses friction brakes (i believe).



There is a black screw in the pic below. From similar rotor replacements in the past, i believe this just needs to be backed out, and a good ol mallet should complete the job. I dont foresee any issues.

IMG_0259.jpeg

In my experience, with past vehicles, that screw isn't holding anything to anything. That's a threaded hole there included in such a way that you can insert another bolt (with the same thread diameter and pitch) and as you 'tighten' the bolt, it 'pushes' the rotor away from the hub.

It's easier, more elegant, and less potentially damaging than using percussive maintenance as we've all done in the past!

My *guess* is that set screw is maintaining the threads from corroding.
 
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I heard this before, I think you’re right. I should probably quit using the mallet
 

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I heard this before, I think you’re right. I should probably quit using the mallet
The mallet is also a legitimate approach if all else fails. WE've ALL been there, especially as a shadetree mechanic wrenching on my own cars in high school!
 

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In my experience, with past vehicles, that screw isn't holding anything to anything. That's a threaded hole there included in such a way that you can insert another bolt (with the same thread diameter and pitch) and as you 'tighten' the bolt, it 'pushes' the rotor away from the hub.

It's easier, more elegant, and less potentially damaging than using percussive maintenance as we've all done in the past!

My *guess* is that set screw is maintaining the threads from corroding.
I've heard this too, but I've also heard they are just there to keep the rotors secured while the vehicles continue down the assembly line. Rotors typically go on with the driveline, but calipers/ tires get installed later on in the process. I have a lot of memories getting these screws out when they seize or strip out on various vehicles.....
 

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2- Where's the brake booster reservoir to pop the cap? I assume you had to re-compress the pistons to fit the thicker/new brake pads
A suggestion for all vehicles when DIY brakes - instead of compressing the fluid back in to the reservoir, open the bleed port on the caliper when you compress. This flushes the old fluid which may be heat stressed or have moisture in it due to moisture intrusion through the seals. Then top off the reservoir and bleed. It’s essentially doing a flush every time you replace the pads. I’ve done this for years and had great results with no seized calipers.
 

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While trying to figure out why my navigation voice instructions disappeared, I noticed the brake assist toggle in vehicle settings. I read about it before but forgot. Default is on (and they recommend that you leave it on). It blends in brakes during regen when conditions calls for it—when it's cold, when regen is reduced (due to full or near full SOC), or going downhill for a long time. Maybe this is the reason for the amount of wear?
 

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While trying to figure out why my navigation voice instructions disappeared, I noticed the brake assist toggle in vehicle settings. I read about it before but forgot. Default is on (and they recommend that you leave it on). It blends in brakes during regen when conditions calls for it—when it's cold, when regen is reduced (due to full or near full SOC), or going downhill for a long time. Maybe this is the reason for the amount of wear?
Higher wear NOTWITHSTANDING, Brakes should ABSOLUTELY NOT wear unevenly.

From an engineering perspective, this is a floating caliper. It 'glides' on the pins that OP showed in his post. It should be imparting equal pressure to both sides of the system. Not only for 'even wear' but, as designed, the intention and force vectors of the brakes squeezing into the caliper and creating a thermodynamic bond that exchanges kinetic for potential energy via thermodynamic conduction ala friction.

It's a long winded way of saying 'if this wasn't improperly installed, it's improperly engineered.'

I, personally, would've fought tooth and nail for this to be covered under warranty. But we all choose our own battles. BRAKES ARE a 'wear item.' BUT, uneven pad wear like this is a symptom of a problem. HOPEFULLY the problem is as simple as re-greasing. If not, and this proves to be endemic to our vehicles, I'd anticipate future recalls and some type of retrofit.

To be clear: due to manufacturing tolerances and stackups in a system, there will be *some* uneven wear, but any more than 5 or even 10% bias is absolutely inappropriate, in my opinion.
 

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Higher wear NOTWITHSTANDING, Brakes should ABSOLUTELY NOT wear unevenly.

From an engineering perspective, this is a floating caliper. It 'glides' on the pins that OP showed in his post. It should be imparting equal pressure to both sides of the system. Not only for 'even wear' but, as designed, the intention and force vectors of the brakes squeezing into the caliper and creating a thermodynamic bond that exchanges kinetic for potential energy via thermodynamic conduction ala friction.

It's a long winded way of saying 'if this wasn't improperly installed, it's improperly engineered.'

I, personally, would've fought tooth and nail for this to be covered under warranty. But we all choose our own battles. BRAKES ARE a 'wear item.' BUT, uneven pad wear like this is a symptom of a problem. HOPEFULLY the problem is as simple as re-greasing. If not, and this proves to be endemic to our vehicles, I'd anticipate future recalls and some type of retrofit.

To be clear: due to manufacturing tolerances and stackups in a system, there will be *some* uneven wear, but any more than 5 or even 10% bias is absolutely inappropriate, in my opinion.
True. QC at Normal does seem hit or miss.
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