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Discussion Starter · #1 ·
Hey folks, I’m new here and figured I’d ask a question about my newly acquired RockShox Reba 110mm suspension for a 29er. It’s a ~2010 model and holds air just fine. The rebound works well and everything seems to function well. The issue I’m having is that when I compress the shock with my body weight on the front of the bike, it feels like there is a hard metal bumper about 3/4 through the shock travel. The shock will not travel any further than that, even with a hard hit.
What are your thoughts?
 

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I’ve had this exact thing happen on an old reba.. What has most likely happened is that the seal at the base of the damper side is failing, and damper fluid has leaked down into the lowers, and the lowers are hydrolocking. And yes, it “feels” like it is bottoming on something solid. You will likely be able to tell if this is the case by unbolting the lowers and seeing if a lot of oil comes out of the damper side.

An 11 year old Reba is due for a tear down and rebuild. Good news is that these are very easy to work on, and for the price of a rebuild kit and new wipers/seals (~60 last time I did this) plus fluids, you end up with a fork that is functionally brand new.
 

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Discussion Starter · #6 ·
I've had this exact thing happen on an old reba.. What has most likely happened is that the seal at the base of the damper side is failing, and damper fluid has leaked down into the lowers, and the lowers are hydrolocking. And yes, it "feels" like it is bottoming on something solid. You will likely be able to tell if this is the case by unbolting the lowers and seeing if a lot of oil comes out of the damper side.

An 11 year old Reba is due for a tear down and rebuild. Good news is that these are very easy to work on, and for the price of a rebuild kit and new wipers/seals (~60 last time I did this) plus fluids, you end up with a fork that is functionally brand new.
Thank you very much for your detailed response!! It sounds like your diagnosis is correct. I loosened the cap on the lower Schrader valve and milky fluid started coming out even without depressing the valve core. It's definitely in need for service. One more question, would you be able to help identify the year model of this fork? I inputted the serial into SRAM's SN checker and it didn't come up.
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Thank you very much for your detailed response!! It sounds like your diagnosis is correct. I loosened the cap on the lower Schrader valve and milky fluid started coming out even without depressing the valve core. It's definitely in need for service. One more question, would you be able to help identify the year model of this fork? I inputted the serial into SRAM's SN checker and it didn't come up. View attachment 1949997 View attachment 1949998 View attachment 1949999
Wait, what I am talking about would be happening on the DAMPER side (not the air spring side) There should not be at any Schrader valve on the damper side.

As far as the year, i don't know, but if you do a search for Reba Service Kit, Each kit generall covers a range of years. If you have a schrader valve at the top and bottom of the air spring side, then you have a Dual Air model.
 

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Discussion Starter · #8 ·
Wait, what I am talking about would be happening on the DAMPER side (not the air spring side) There should not be at any Schrader valve on the damper side.

As far as the year, i don't know, but if you do a search for Reba Service Kit, Each kit generall covers a range of years. If you have a schrader valve at the top and bottom of the air spring side, then you have a Dual Air model.
Yes, I have a dual air model. I was planning on contacting SRAM about the year so I can get the proper servicing kit. I have a Schrader on the top and bottom of the air side. I released some pressure out of the bottom of the air side and milky oil sprayed out. I'm assuming this is due to leaky seals.

@Mountainfrog, I'm not sure how much sag I'm running. I measured the length of the stanchion at rest and I'm at 122mm.
 

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I've had this exact thing happen on an old reba.. What has most likely happened is that the seal at the base of the damper side is failing, and damper fluid has leaked down into the lowers, and the lowers are hydrolocking. And yes, it "feels" like it is bottoming on something solid. You will likely be able to tell if this is the case by unbolting the lowers and seeing if a lot of oil comes out of the damper side.

An 11 year old Reba is due for a tear down and rebuild. Good news is that these are very easy to work on, and for the price of a rebuild kit and new wipers/seals (~60 last time I did this) plus fluids, you end up with a fork that is functionally brand new.
This happened with my motion-control Reba too....a few times.
 

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Yes, I have a dual air model. I was planning on contacting SRAM about the year so I can get the proper servicing kit. I have a Schrader on the top and bottom of the air side. I released some pressure out of the bottom of the air side and milky oil sprayed out. I'm assuming this is due to leaky seals.
I don't think that has anything to do with the issue you described. That Schrader valve is for the negative air chamber, which is in the uppers, not the lowers. And a leaky seal at the base of the uppers on the air side would not cause the issue you are having.
 

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Looks like about a 2007... Sounds like a hydro-lock issue to me, but the bottom line is, you have an old fork that needs service. You can DIY it and replace all the seals - that is probably the only cost-efficient option. Once you take it apart, it will become apparent what the problems are.
 

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Here is the relevant rebuild guide: https://www.servicearchive.sram.com...06 Pike Reba RVL Dual Air Service Guide_0.pdf

You want this rebuild kit: Rock Shox Fork Full Rebuild Service Kits
look at the one labeled Reba/Recon/Revelation/Pike Dual/Solo Air Service Kit with your year listed below (2005-2008)

You will want some dust wipers / seals. There are several options (original parts and aftermarket) that will fit. My only advice would be to stick with flanged (vs flangless) as they are a LOT easier to install without a special tool. I've had good luck with the stock Rock Shox ones as well as the ones from Enduro / Real World Cycling. SKF make nice ones, but the ones I have a flangeless (I have a tool for it).

For oil, I use Maxima 5 weight Fork Oil for the damper side.

For the lowers, I've used Maxima 15w fork oil (same link as the 5W, just in 15w instead), Motorex PowerSnt 5w-40 (that was recommended by some on on this site since I could not find Powergliss), some sort of Castrol synthetic motor oil (recommended by the folks at Enduro / RWC). Honestly, they all work fine. I think I actually liked the 15w Maxima Fork slightly better than the others, but opinions on this vary, and become passionate. Don't get too caught up in this. 95% of an oil's performance comes down to simply DOING the lower oil changes regularly. I just got some Maxima Plush 10W. I'm sure it is not going to be drastically different than anything else.

A tub or tube of slick honey is great for greasing the air piston.

If you don't have snap ring pliers, you will need to get a pair. Crescent wrench works fine for the top caps if you don't have the big socket. Rubber of plastic headed mallet is also useful.

Good luck!
 

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Too much oil in the damper also causes the fork to hit a stop (hydro lock) about 3/4 through the travel. It may have happened when/if the last owner serviced it. Make sure you get the oil level correct!
 

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Discussion Starter · #16 ·
Hey all! Just wanted to give you an update. When I took everything apart, I found that the baseplate on the dual air slider was blown apart. I searched online everywhere and could not find a new part or assembly in stock. I thought out of the box a little and designed a part with similar function on Fusion 360. I 3D printed it with PETG (pretty strong and resistant to oil). It serves its purpose and functions well!

I did have one question/issue I ran into. During assembly, I removed the rubber spacer on the air side, as I read it would improve my travel. After assembly, I noticed the stanchions didn't sit as high as they did before the rebuild. I have yet to measure, but I believe the sitting height was reduced by maybe 30mm. What would cause this? Positive pressure is 160psi and negative is about 130psi.

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