The 24 Hours of Lemons Forums → Lemons Tech → Who has redone shocks with new oil?
Looking to "upgrade" our suspension. Of course, now that we've cut our springs and dropped our beefy Metro back down to it's usual ride height, we are under-damped.
I've read various threads on other forums that have discussed drilling out the stock metro shocks and filling with a heavier fork oil.
Anyone have any experience with this?
Thanks!
Haven't yet, but with 3 of 4 floppy shocks, I plan to. I hear it only works on double tube shocks though? - Doubt the Metro has those... Drill a hole near the top, empty/refill and weld up... I'll probably weld on a port so I can experiment with different oil weights...
Haven't yet, but with 3 of 4 floppy shocks, I plan to. I hear it only works on double tube shocks though? - Doubt the Metro has those... Drill a hole near the top, empty/refill and weld up... I'll probably weld on a port so I can experiment with different oil weights...
Twin tube shocks are the norm. Monotubes are what Koni and Bilstein use and are the pricey ones, so the Metro will have twin tubes. That said, if they are simply worn, higher weight oil might help, but once blown (floppy), the new heavy weight oil will likely just puke out through the seal. We lost the seal on our left rear at Nelson and all the oil puked out at once right onto our hot tailpipe. A nice fireball ensued. Luckily, there isn't much oil in a shock and the fire went out immediately.
The front struts (yes I said struts) for some cars can be rebuilt. The tops unscrew and then you pour out the old oil and pour in new motorcycle fork oil (or engine oil???). I know that the original Datsun struts for a 510 are that way, as are most of the late 60s early 70s Datsun struts.
So for the front of your metro, you should drop the struts out and check that out, it may just require an oil change.
Another alternative, which works for both strut cartridges and Shocks, is to go to the Monroe Shock web page and download their application catalog.
1. Find the part number for the metro Front and Rear strut/shock.
2. Go find that specific strut/shock and write down the specs: diameter of strut cartridge, length of strut cart, length of travel, anything else interesting. For the rear shocks, know the max and min length, and type of attachment upper and lower.
3. Then go to the cross reference charts and search for similar size/length/attachment, and also shorter length/same attache mt/same diameter parts, write down all those numbers.
4. then go back and find out what cars those fit.
5. Then pick from those cars, for stiffer shocks, pick a heavier car, like a Chevy Camero rear shock that is a little shorter, but has the same attachment types U&L. For a softer shock, pick a lighter car (tough to do for a Metro). For a lowered car, pick shorter overall and shock length. for a Rally set up, pick a longer travel shock.
6. Hit JY, find the right parts, unbolt, take home, be happy.
Spinnetti wrote:Haven't yet, but with 3 of 4 floppy shocks, I plan to. I hear it only works on double tube shocks though? - Doubt the Metro has those... Drill a hole near the top, empty/refill and weld up... I'll probably weld on a port so I can experiment with different oil weights...
Twin tube shocks are the norm. Monotubes are what Koni and Bilstein use and are the pricey ones, so the Metro will have twin tubes. That said, if they are simply worn, higher weight oil might help, but once blown (floppy), the new heavy weight oil will likely just puke out through the seal. We lost the seal on our left rear at Nelson and all the oil puked out at once right onto our hot tailpipe. A nice fireball ensued. Luckily, there isn't much oil in a shock and the fire went out immediately.
Yeah, Mine aren't leaky, just underdamped.. thicker oil ought to do the trick. More amazingly, I really didn't notice on track. Handled really good, even with only one good shock. Worth an experiment!
Thanks guys... all the info helpful. I know the Metro shocks can be drilled, but a little fuzzy on the DIY.
I've read that you should drill about 1 1/2" from the top, anyone agree/disagree?
People have mentioned "using a really sharp bit" so you develop a metal strip that is drilled out instead of shavings/pieces that could fall back into the shock, suggestions? Cobalt?
What size drill bit? Close it with a self tapping screw dipped in epoxy?
I've heard people fill with varying weights of fork oil, and I've even found a pretty good chart below. Others just recommended going to the closest Harley Davidson shop and buying medium weight fork oil.
Is there really a shock oil called "White Power"? What the klux?
"White Power" is an old dirt bike specialty shock company that's been around for 25 years or so. The founder's last name is White, but I'm not exactly sure why he went with White Power. They were a popular aftermarket upgrade on Austrian-built KTMs...
Well... I've done what you suggested for the Metro (part no 71918) which has a front Monroe B2 style strut with body length of 12.5, comp length 12.5, Ext. length 17.825 and travel of 5.625. The closest somewhat same size for front is for a 89-94 Nissan 240SX (part no 71848) that is a B2 style with body length of 12.625, comp length of 10.5, ext length of 16.5, and travel of 6.0.
For the rear (part no 71852) has a B8 style with body length of 13.375, comp length of 13.375, ext length of 20.250, and a travel of 6.875. The closest somewhat same size is for a 86-89 acura integra (part no 71795) with a B8 style, body length of 12.875, comp length of 12.875, ext length of 18.75, and travel of 5.875.
So, if I'm right then I need to find used 89-94 Nissan 240SX front struts and used 86-89 Acura Integra rear struts? Both cars are heavier and shock sizes are comparable. Am I thinking of this right?
The front struts (yes I said struts) for some cars can be rebuilt. The tops unscrew and then you pour out the old oil and pour in new motorcycle fork oil (or engine oil???). I know that the original Datsun struts for a 510 are that way, as are most of the late 60s early 70s Datsun struts.
So for the front of your metro, you should drop the struts out and check that out, it may just require an oil change.
Another alternative, which works for both strut cartridges and Shocks, is to go to the Monroe Shock web page and download their application catalog.
1. Find the part number for the metro Front and Rear strut/shock.
2. Go find that specific strut/shock and write down the specs: diameter of strut cartridge, length of strut cart, length of travel, anything else interesting. For the rear shocks, know the max and min length, and type of attachment upper and lower.
3. Then go to the cross reference charts and search for similar size/length/attachment, and also shorter length/same attache mt/same diameter parts, write down all those numbers.
4. then go back and find out what cars those fit.5. Then pick from those cars, for stiffer shocks, pick a heavier car, like a Chevy Camero rear shock that is a little shorter, but has the same attachment types U&L. For a softer shock, pick a lighter car (tough to do for a Metro). For a lowered car, pick shorter overall and shock length. for a Rally set up, pick a longer travel shock.
6. Hit JY, find the right parts, unbolt, take home, be happy.
I can't believe someone else is running a Lemons Metro.
Anyway, I have looked high and low into how to improve the crap dampers on the Metro Gnome. In the end , I ground off the crimp at the top of the strut housing and took out the whole inner tube assembly and dumped out the old oil. What I found was that the valving is setup to have nearly no compression dampening at all. Bad for race car. If you take apart the shaft valve you can close off the bump vents and get some bump damping. I used ATF for oil. It's cheap and is about right. Once you are done with that, weld a cap over the end and re-install.
The front and rears are the same save for the casings. You could cut off the mount from a front strut and install it in the rear if you wanted to. Truth is, if you put solid struts in place of the rear shocks on a Metro it would probably handle better. Metro "Hardtail" LOL.
On our Civic, the front struts are not rebuildable and one had a leak at the rod seal. So we drilled a hole at the bottom, pumped all the old oil out and brazed a 10mm nut to the bottom of the housing. We then filled the shock with ATF, kept pumping it until the bubbles quit coming out, then kept the shock fully compressed while holding it upside down and put a 10mm bolt with a copper washer in as a plug. Then we flipped the shock to its normal position and worked the damper rod, this forces the air in the shock into the outer tube. The rebound damping was a LOT stiffer. It worked great until the one seal blew out entirely.
We left the rears alone since it was so light after gutting and we had cut 2 1/2 coils off of the springs which stiffened them a good bit, a lot of damping and light in the rear combined with stiff springs would have meant a twitchy car. We wanted the car to have predictable handling and it was definitely that.
White Power is now WP Suspension. They made some of the finest aftermarket shocks and forks for dirt bikes for many years. I had a set of their forks on an XR600 Honda, good stuff.
Yeah... ours is a natively powered Metro. UNDERPOWERED! So our handling is going to have to be spectacular, and at this point it is craptacular. Thanks for the info.
How did you decide how much oil to use?
For the compression dampening, are there holes in the piston that let the oil through? Are these the bump vents you are referring to? The holes in the inner cylinder are to help with rebound dampening, correct?
I can't believe someone else is running a Lemons Metro.
Anyway, I have looked high and low into how to improve the crap dampers on the Metro Gnome. In the end , I ground off the crimp at the top of the strut housing and took out the whole inner tube assembly and dumped out the old oil. What I found was that the valving is setup to have nearly no compression dampening at all. Bad for race car. If you take apart the shaft valve you can close off the bump vents and get some bump damping. I used ATF for oil. It's cheap and is about right. Once you are done with that, weld a cap over the end and re-install.
The front and rears are the same save for the casings. You could cut off the mount from a front strut and install it in the rear if you wanted to. Truth is, if you put solid struts in place of the rear shocks on a Metro it would probably handle better. Metro "Hardtail" LOL.
That's exactly what we're trying to figure out with this car. The roll we expect to fix with a beefed up sway in the back (the front sway is more than enough, we need some oversteer... SOMEHOW!)
We left the rears alone since it was so light after gutting and we had cut 2 1/2 coils off of the springs which stiffened them a good bit, a lot of damping and light in the rear combined with stiff springs would have meant a twitchy car. We wanted the car to have predictable handling and it was definitely that.
I use Gnarley Davidson 20w fork oil in the Killer Bee. I'm tempted to go heavier, and I hear 20W-50 works really good, but worry how it will hold up for hours on end. The HD has anti-foaming agents in it and though they aren't great at least they don't fade. Anyone else have foaming/fading issues?
MGBs use Armstrong Lever action shocks, so yeah, this is kinda like comparing apples to bacon. Hey look, I found another way to talk about bacon!
does the 20W work well? my MGB's a bit spongy and wondering if it's just bad oil or blown shocks, i know the rear springs are crap, but idk if the shocks need replacement too
Well... I've done what you suggested for the Metro (part no 71918) which has a front Monroe B2 style strut with body length of 12.5, comp length 12.5, Ext. length 17.825 and travel of 5.625. The closest somewhat same size for front is for a 89-94 Nissan 240SX (part no 71848) that is a B2 style with body length of 12.625, comp length of 10.5, ext length of 16.5, and travel of 6.0.
The rears should work great, its a shorter shock. But the fronts, since its a strut cartridge, will probably not work. Look for a shorter cartridge body, then you can just fill the bottom of the strut housing with steel washers or a steel ring.
But did you take apart the Metro struts?? they are cartridge or an older shock strut (which you could just refill with new oil)>
Car is at the cage-builder still. We've not taken apart the shocks yet. I will plan on doing it when we get the car back, was just tryiing to do some leg work while I had the free time.
I believe they can be re-filled with new oil, since other geometroforum.com member have done it.
The rears should work great, its a shorter shock. But the fronts, since its a strut cartridge, will probably not work. Look for a shorter cartridge body, then you can just fill the bottom of the strut housing with steel washers or a steel ring.
But did you take apart the Metro struts?? they are cartridge or an older shock strut (which you could just refill with new oil)>
An aquaintance of mine says he stiffens his tough-truck suspension with air. By this I mean he stuffs tennis balls in the coil springs. He says it works wonderfully. Think it will pass tech?
does the 20W work well? my MGB's a bit spongy and wondering if it's just bad oil or blown shocks, i know the rear springs are crap, but idk if the shocks need replacement too
Yes, quite well. So long as they are not leaking you should be ok. Its a cheap way to see if they just needed refreshing. I also clean out the shock valves and add a shim underneath the spring to stiffen them up. I once bought a set of competition valves (25% stiffer supposedly) and the only difference was an added shim. 6 cents beats $35 anyday.
ONO THEIR LEAKING!
On our Civic, the front struts are not rebuildable and one had a leak at the rod seal. So we drilled a hole at the bottom, pumped all the old oil out and brazed a 10mm nut to the bottom of the housing. We then filled the shock with ATF, kept pumping it until the bubbles quit coming out, then kept the shock fully compressed while holding it upside down and put a 10mm bolt with a copper washer in as a plug. Then we flipped the shock to its normal position and worked the damper rod, this forces the air in the shock into the outer tube. The rebound damping was a LOT stiffer. It worked great until the one seal blew out entirely.
Just curious about this. When you say you kept pumping until the bubbles quit coming out, what do you mean? You hold the shock upside down and push the damper rod in and out?
I just pulled apart the front strut of a Saturn... unfortunately all of the ones I have the top is swaged, so it can't be safely disassembled. There is enough material in the bottom that I could drill through then cap it though.
One more question related to this... how much pressure is there usually in a gas charged strut/shock? I know the ones I am messing with are pressurized... if I were to plug them hole with a schrader valve to re-pressurize them, any idea how much air to add?
Well... I've done what you suggested for the Metro (part no 71918) which has a front Monroe B2 style strut with body length of 12.5, comp length 12.5, Ext. length 17.825 and travel of 5.625. The closest somewhat same size for front is for a 89-94 Nissan 240SX (part no 71848) that is a B2 style with body length of 12.625, comp length of 10.5, ext length of 16.5, and travel of 6.0.
For the rear (part no 71852) has a B8 style with body length of 13.375, comp length of 13.375, ext length of 20.250, and a travel of 6.875. The closest somewhat same size is for a 86-89 acura integra (part no 71795) with a B8 style, body length of 12.875, comp length of 12.875, ext length of 18.75, and travel of 5.875.
So, if I'm right then I need to find used 89-94 Nissan 240SX front struts and used 86-89 Acura Integra rear struts? Both cars are heavier and shock sizes are comparable. Am I thinking of this right?
mackwagon wrote:The front struts (yes I said struts) for some cars can be rebuilt. The tops unscrew and then you pour out the old oil and pour in new motorcycle fork oil (or engine oil???). I know that the original Datsun struts for a 510 are that way, as are most of the late 60s early 70s Datsun struts.
So for the front of your metro, you should drop the struts out and check that out, it may just require an oil change.
Another alternative, which works for both strut cartridges and Shocks, is to go to the Monroe Shock web page and download their application catalog.
1. Find the part number for the metro Front and Rear strut/shock.
2. Go find that specific strut/shock and write down the specs: diameter of strut cartridge, length of strut cart, length of travel, anything else interesting. For the rear shocks, know the max and min length, and type of attachment upper and lower.
3. Then go to the cross reference charts and search for similar size/length/attachment, and also shorter length/same attache mt/same diameter parts, write down all those numbers.
4. then go back and find out what cars those fit.5. Then pick from those cars, for stiffer shocks, pick a heavier car, like a Chevy Camero rear shock that is a little shorter, but has the same attachment types U&L. For a softer shock, pick a lighter car (tough to do for a Metro). For a lowered car, pick shorter overall and shock length. for a Rally set up, pick a longer travel shock.
6. Hit JY, find the right parts, unbolt, take home, be happy.
Hey that is agreat news! (about Monroe's web page) I used to have the same thing in catalogs and would spend hours pouring over shocks trying to find an economical shock to do what I wanted it to do..
You don't need to buy Koni double adjustables if there is a cheap shock that will achieve the same thing..
One more question related to this... how much pressure is there usually in a gas charged strut/shock? I know the ones I am messing with are pressurized... if I were to plug them hole with a schrader valve to re-pressurize them, any idea how much air to add?
Shocks usually have 100psi of nitrogen in them. Temperature changes will have a bigger effect on air. Air is only 80% nitrogen so put 80psi in it, what could go wrong?
does the 20W work well? my MGB's a bit spongy and wondering if it's just bad oil or blown shocks, i know the rear springs are crap, but idk if the shocks need replacement too
Thicker oil in an MG shock is only a band aide.. take them apart, clean them up, and replace the rubber.. I found careful use of a little wet or dry sand paper to help a lot in dealing with those spots in the cylinders that have rust rings from sittingworked for me..
When replacing the rubber I used niophreme instead of rubber and haven't needed to rebuild mine since 1974 when I did them the first time..
I switched to 40 weight fork oil since most of my use for the MGTD is vintage sports car racing. That would be too stiff for the street and on chilly mornings the first few laps the handling is terrible. It's like I'm driving a bus..
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