Hydraulic bump stops on a D2

Jeff Blake

Well-known member
May 6, 2016
403
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Pacific Beach, San Diego
I have 90mm extended poly stops right now, but they're not long enough. I like that hydraulic stops are adjustable, and would make big bumps at speed much more pleasant - especially for the rear.

Has anyone done it?

There's not much space. I can only think of two ways, put it inside the spring in the rear (which I don't want to do), or cut a half circle hole on the inside frame, and weld in pinch can mounts for the stops, and possibly need to extend the contact pad on the axle.


Or keep it simpler and modify the frame mount to accept any standard threaded poly or rubber bump stop. Are there any adjustable ones?
 

SGaynor

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Dec 6, 2006
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Yes. Search function is not working (at least for me), there was a thread or two on them. Probably 10+ years ago now.

They were mounted inside the spring, IIRC. And they dramatically improved driving on washboard roads, ie, go faster, less bumps.
 

K-rover

Well-known member
Jan 15, 2010
1,965
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Raleigh, NC
I dont see the point in hydro bump stops unless you are doing high speed stuff. Im using progressive foam bumpstops that mount on the shock shaft. They have a progressive rate as it gets compressed so its not a hard hit.
Hydro bumps are sweet! I just think its a bit over kill. If you had coilovers and a linked suspension Id say go for the hydros.
 

SGaynor

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Found it:

 

Jeff Blake

Well-known member
May 6, 2016
403
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Pacific Beach, San Diego
I dont see the point in hydro bump stops unless you are doing high speed stuff. Im using progressive foam bumpstops that mount on the shock shaft. They have a progressive rate as it gets compressed so its not a hard hit.
Hydro bumps are sweet! I just think its a bit over kill. If you had coilovers and a linked suspension Id say go for the hydros.
I already need to employ a welder to do something custom, so I might as well go hydraulic for a little more $. Rather keep the bumps separate from the shocks and coils if possible. I think I could benefit a lot from it too. I have one fat ass that loves to shake its' stuff


Found it:

Good info. Problem is those 1.5" jounce shocks are a lot less common, and much more expensive. Not keen on $300 per bump. You also can't fit a lot of travel with that style.

I did some measurements again.. I have 5" of shock travel (21.25 installed length, 26.14" extended, 16.14" collapsed)
Rear bump to axle is 3.75", and more like 4.2" if you exclude the tiny cone on the bump stop

Sooo it actually looks like I'm good.. though I'm putting in new rear springs and may gain an inch of lift

Bigger issue is my rear panhard frame mount to radius arm axle mount is only 3".. I think I can shave some metal down and make it 3.5"... hmmm


A more traditional hydro bump uses pin or pinch style mounting cans. There's no way to fit a can on the inside of the frame, the only possible option is to cut a section out of the inside part of the frame (taking out most of a body mount support), and welding the can at least half into the frame rail. I think I'd have to use a pin style can then in that case. Is this a viable idea?

The more realistic option is a pin style can inside the upper rear spring mount. With the pin style, you slide the hydro bump in from the bottom, and secure a nut at the top. there's enough gap between the body and spring perch to slide the nut in.
 

SGaynor

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Dec 6, 2006
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Good info. Problem is those 1.5" jounce shocks are a lot less common, and much more expensive. Not keen on $300 per bump. You also can't fit a lot of travel with that style.
I don't know how much travel you are looking for, but Thom was running 5" lift and Flyfisher was 3". Kind of hard to get more than what Thom had, short of redoing the whole suspension

A more traditional hydro bump uses pin or pinch style mounting cans. There's no way to fit a can on the inside of the frame, the only possible option is to cut a section out of the inside part of the frame (taking out most of a body mount support), and welding the can at least half into the frame rail. I think I'd have to use a pin style can then in that case. Is this a viable idea?

The more realistic option is a pin style can inside the upper rear spring mount. With the pin style, you slide the hydro bump in from the bottom, and secure a nut at the top. there's enough gap between the body and spring perch to slide the nut in.
chopping and redoing the frame is easier/cheaper than the jounces? OK...
 

Jeff Blake

Well-known member
May 6, 2016
403
11
Pacific Beach, San Diego
I don't know how much travel you are looking for, but Thom was running 5" lift and Flyfisher was 3". Kind of hard to get more than what Thom had, short of redoing the whole suspension


chopping and redoing the frame is easier/cheaper than the jounces? OK...
Didn't say it was easier. The JounceShock is very appealing for the straightforward installation, but compressed length is 4.7", which would reduce my current up-travel 1.2". I could try and get more lift, but I'm having a hard time with that, already on HD springs and 2" spacers.

I found this helpful.
Good info, wish they talked more about mounting methods though.

Tying a bump stop can into the inner frame frail would be a lot of work, and I don't really know if it's a viable idea or not.


I have another idea, and some questions for the D1 guys

- is the rear upper spring perch fully underneath the body, and what is the gap between the body and perch?

Terrafirma makes a bolt on hydraulic bump stop mounting kit, TF543 (rear) and TF542 (front) for the D1/RRC/90. Most of TF's D1 spring parts work on my D2, so this might as well. The rear kit mounts inside the spring

It looks like it won't work, because it extends upward outside the spring perch too far. I only have like a 0.5" gap between perch and body on my D2. But possibly with some modification...?
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SGaynor

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Dec 6, 2006
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Bristol, TN
I have 90mm extended poly stops right now, but they're not long enough. I like that hydraulic stops are adjustable, and would make big bumps at speed much more pleasant - especially for the rear.
Didn't say it was easier. The JounceShock is very appealing for the straightforward installation, but compressed length is 4.7", which would reduce my current up-travel 1.2". I could try and get more lift, but I'm having a hard time with that, already on HD springs and 2" spacers.
I'm really confused here.

You say that 90mm (3.54") is too short and want longer, but then 4.7" (120mm) is too long because you will lose the 1.2" of travel, which is where you are today...which is too short?
 

Jeff Blake

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May 6, 2016
403
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Pacific Beach, San Diego
I re-measured, and have 5" of up travel, 5" down travel in the rear shocks. So I could actually be running 2.75" ish bump stops, as long as I fix my other clearance issues. Plus Im putting in new rear springs and may gain another inch

So I looked around on the net, and the D1 rear upper perch looks pretty much the same as the D2. However looking at the TF543 instruction manual, it shows this picture:
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which is weird, because the rear upper spring perch is nowhere near that exposed on a D1/D2, yet this part says it works on a D1

Am i missing something?

Instructions: http://www.terrafirma4x4.com/instructions/fitting/TF543.pdf
 

proper4wd

Well-known member
Jun 11, 2015
65
14
boston
the video you posted is literally of a disco or RRC and shows how it fits. and yes the bumpstop also definitely breaks on that hard hit towards the end as you can see it does not return to its static position!!! terrafirma garbage.

for the record devon4x4 also make and sell these brackets, it may be the same part branded through TF though. not sure.
 

ERover82

Well-known member
Nov 26, 2011
3,059
41
Darien Gap
the bumpstop also definitely breaks on that hard hit towards the end as you can see it does not return to its static position!!! terrafirma garbage.
Hold on, video OP commented "Stop bump works ok. Problem was on the top. The top screws were tightened too much."
 

CORover

Well-known member
Jun 11, 2007
494
13
Colorado, USA
D1, is the rear upper spring perch fully underneath the body, and what is the gap between the body and perch?

Yes mostly, just a small portion is outside the body, very small portion. When I was installing a captive mount for the top of the spring, I could not fit it in. Then I figured out my rubber body mounts had collapsed, so I did those and got to 1/2 to 3/4 of an inch clearance. Now I wish I had done a small, 1 inch body lift when I was messing with the mounts. That should start a whole new flame...
 

Jeff Blake

Well-known member
May 6, 2016
403
11
Pacific Beach, San Diego
D1, is the rear upper spring perch fully underneath the body, and what is the gap between the body and perch?

Yes mostly, just a small portion is outside the body, very small portion. When I was installing a captive mount for the top of the spring, I could not fit it in. Then I figured out my rubber body mounts had collapsed, so I did those and got to 1/2 to 3/4 of an inch clearance. Now I wish I had done a small, 1 inch body lift when I was messing with the mounts. That should start a whole new flame...
Yeah, so same as D2 it sounds like. Not sure how this kit would fit... so I sent terrafirma an email about it. I've emailed them before about the front dislocation cones, and rear inverse dislocation cones - catalog says D1 only, but terrafirma told me D2 works as well. If they work, I'll pull the trigger - the appeal of a bolt on solution is too good

Next on the todo list is trimming rear fenders to fit my 35s... I'm scared to cut up the doors but it looks necessary
 

Jeff Blake

Well-known member
May 6, 2016
403
11
Pacific Beach, San Diego
Put them on the radius and trailing arms. Weld cans to the outside of the frame.
Interesting idea. What is that bump travel, and how far from the arm at ride height? I'll take a look under the truck tomorrow to see if that's viable on a D2. The d2 arms are awfully thin.. a welded contact plate would be necessary I think. No longer/HD trailing arms that I know for a d2.

I have the same upper retainer / lower cone setup, which would be nice to keep, but the bolt-on hydraulic bump stop kit would provide all those benefits as well, and is bolt-on, a major plus
 

Jeff Blake

Well-known member
May 6, 2016
403
11
Pacific Beach, San Diego
I took a leap of faith and ordered the TF543 rear kit, and two bump stops. It's heavy. The mounting kit alone is at least 30 pounds.

No idea how this is going to fit without body cutting. The tube above the perch sticks out 3.5".......... interesting. The manual included says "Fits Defender 90". That's promising..

Cool design for the spring relocation, but not sure if it's better than my upper retainer / lower cone current setup though.

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