Dobinson's MRR long term review

[nj swb]

Unfortunately it's the shocks, not the isulator (mind you, my insulator has seen better days). The bushes were fubar and I had them replaced, I just never got around to putting the shocks back in until yesterday. To prove this, today I will replace those shocks and prove the knock is that the MRR's on the rear are flogged.

Dobinson supplied reservoir pistons pre-fitted with O-ring seals that were too small, so gas leaked past the seals and created a "dead zone" that allowed a small amount of undamped movement. If yours were re-built using the same incorrect O-rings, perhaps that's your problem too?

[sharkcaver]

Dobinson supplied reservoir pistons pre-fitted with O-ring seals that were too small, so gas leaked past the seals and created a "dead zone" that allowed a small amount of undamped movement. If yours were re-built using the same incorrect O-rings, perhaps that's your problem too?

Mine have not been rebuilt, just had lower bushes replaced. They more than likely need it, but I'm over the issues, it's time to move on. The shocks worked fine (bar the initial hose failure) for near 50K. BTW, I removed those shocks yesterday, knock gone.

The one other thing that annoys me greatly: no standardisation. As shown in your rebuild example.

They had a big issue getting spare bushes for mine, I was without them for months. They sent me a new set instead would you believe - (how hard can a bush be to obtain - and then get it wrong by supplying a bush 2mm shorter than standard). The problem with the new ones was that they were not piggy backed. I like the piggy backed version myself. No issues trying to mount the res anywhere, but it needs to be set up correctly. In hindsight, maybe I should have accepted the new ones, cause I wouldn't be where I am now.

It appears they now supply some vehicles as piggy backed reservoirs, and some not. The Paj is now one of those not piggy backed.

I fully understand the principle of design changes over time, that is necessary to maintain your product at the top of its game. My thoughts are that because some (if not all) the compnentry is outsourced from poorer nations, they have lost control of design changes and spares.

Don't get me wrong, Dobinson is a great Aussie business and I wish them all the success in the world. I have personally met the owner and toured his Rockhampton manufacturing facility with him. But what do I do? I can call or email him direct should I wish. Since early November both my supplier and the Dobinson owner are aware I have failed strut issues once again and this time I have heard nothing back. As I said, it seems the party is over.

So with failed struts and shot rears I had to make a decision. Stay with a product that has given me some headaches in the past, or move onto a different product hoping for a better result. I have chosen the latter. Only time will tell if this was the correct decision.

[erad]

On the subject of which shock absorber to use, has anyone here tried Konis? Right now, I don't need new dampers, but I used to run them om my cars and they were brilliant, and when failure did occur, it was readily repaired by the local agent. As far as I can see, the main problem with them is the price. From memory, Kiwi uses them on his NS and he certainly has been to places where most of us would not dare to go.

[old Jack]

If you go off road and really need wheel travel then you need to consider the shocker extended length as they vary greatly. Last October long weekend when we were in the Flinders Ranges together Twisted 32 did some real life rear suspension droop measurements on his NW as well as M&M, NJswb, Pajerp 12 and Raorback 481, and from memory the Dobinson MRR had much more travel than the Bilstein but the Bilstein had more than the Old Man Emu.

OJ.

[Lost1]

Hi Erad, Mucked around with club level motorsport in the late 80's early 90's. New a few that had Koni's fitted to rally cars and I used them on car that ran in lap dashes or the occasional hill climb.

Can't recall any Koni shock failures on the rally cars. As some have said on this forum the hydraulic shock gives a slightly softer ride than say a gas charged Bilstein. Koni's will be physically larger in diameter than a large bore monotube shock. Not sure if clearance could be an issue in some instances like some have experienced with Tough Dog.

I think Koni make a very good shock and should considered when updating your suspension.

[Pwoffey]

On the subject of which shock absorber to use, has anyone here tried Konis? Right now, I don't need new dampers, but I used to run them om my cars and they were brilliant, and when failure did occur, it was readily repaired by the local agent. As far as I can see, the main problem with them is the price. From memory, Kiwi uses them on his NS and he certainly has been to places where most of us would not dare to go.

I have had Koni Raid 90s on the front of my Paj NW since almost new (now at 133,000km). Kieran recommended them. I also had Koni 88's on the rear until the odo read about 120,000. No problems with the fronts. The passenger side rear shock gave out at 120k and my suspension guy said the driver's rear was not at full strength either. No visible damage to the casings. Presumably it's the seals. I was just about to go on a 12,000km trip up to to Arnhem Land and other assorted places. Things were a bit rushed, but I decided to put on some Bilsteins (about half the price?? if I recall), and get the Koni's refurbished. I'll put them back on when the Billies give out. So is 120,000km a reasonable life for something as expensive as a Koni? Depends how you look at it. That 120,000km had a fairly high proportion of towing and doing very corrugated outback tracks. Also a fair bit of suspension-testing rocky and washed out tracks with ruts (eg. Davies Plains Track, Wurramurra Track on Mt Elizabeth Station etc). Nothing that would require a winch but challenging nonetheless, at least for me. The combination of Lovell Springs and Koni shocks performed extremely well, with little if any noticeable fade. The Billies have only been on for about 13,000km and are also very good, maybe the rear seems a little less composed when not towing but that's just a very subjective impression. We'll see how long the Billies last. The Koni's are re-buildable, albeit at almost the cost of a new Bilstein!


I also had Konis on my camper trailer. After about 60,000km one of them began to leak. It had been hit very hard by some rocks and the casing was quite badly damaged. I decided not to repair this. I put on a new pair of Ironman Foam Cell Pro shocks and kept the good Koni as a spare. At least on the trailer the Ironman shocks have been fine on several long outback trips (Cape Yorke/western QLD and NT/Arnhem Land). I think the failure of the Koni in this instance was just bad luck (or my bad driving).


I really like the ride you get with Konis and the lack of fade and I will use them again. But you pay a lot for it. If my new Billies last into the 100,000s km then the equation really starts to change. But it's early days.

[twisted32]

If you go off road and really need wheel travel then you need to consider the shocker extended length as they vary greatly. Last October long weekend when we were in the Flinders Ranges together Twisted 32 did some real life rear suspension droop measurements on his NW as well as M&M, NJswb, Pajerp 12 and Raorback 481, and from memory the Dobinson MRR had much more travel than the Bilstein but the Bilstein had more than the Old Man Emu.

OJ.

Correct OJ, although the Ultimates also gave full suspension travel same as the Dobos (ie suspension geometry not shock length was the limiting factor).
I recently did full travel checks on the front of my NW, and with only 200mm travel from bump stop (primary on lower control arm) to full droop (measured at the hub) every little bit helps. FYI 10mm piston length equaled about 15mm wheel travel.
Should get around to doing the rear travel checks over the next week or so...

[sharkcaver]

If you go off road and really need wheel travel then you need to consider the shocker extended length as they vary greatly. Last October long weekend when we were in the Flinders Ranges together Twisted 32 did some real life rear suspension droop measurements on his NW as well as M&M, NJswb, Pajerp 12 and Raorback 481, and from memory the Dobinson MRR had much more travel than the Bilstein but the Bilstein had more than the Old Man Emu.

OJ.

In regards to the front, I have no means to compress the unit to measure travel, But I can confirm both the Bilstein and MRR do not restrict droop. The limiting factor is the sway bar.


The rear is a different story. Both the OME and the Bilstein are of similar free length and both of these restrict droop. The shock bottoms out before the suspension components, restricting the amount of droop.

The MRR on the other hand, has similar stroke length, but at a different position (50mm longer). With the MRR, the limiting factor on droop is again, the sway bar. What concerns me is the compressed length. I have no way to compress my suspension to the bump stop, but from rudimental measurements I took, topping out the MRR by the bump stop will be very close. That can cause some damage if uncontrolled.

[Lost1]

A few on this site have used bilstein rears for a Landcruiser 100 Series. This gave an extra 30-40mm of down travel on the rear.

There were a couple of tweaks required to make them fit such as making a small sleeve to go into the bottom bush and a swapping the top shock rubbers from memory. This gave slightly more down travel. Be aware the fully compressed shock length was longer than the Pajero shock. But not sufficiently longer that the shocks would bottom out before hitting the suspension bump stops.

Not sure what affect this would have on the service life of the shock if they are being regularly compressed through a range of movement the shock would not normally endure.