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Thread: Front struts - U-van versus A-car - Interchange?

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    Senior Member turbokinetic's Avatar
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    Default Front struts - U-van versus A-car - Interchange?

    Hey folks.

    I have found two different part number struts for front struts for the U-van and the A-cars.

    The U-van has part number 71820
    The A-cars have part number 71771

    The measurements listed in the website for Monroe are the same within a few thousandths of an inch.

    Has anyone tried this interchange? if so was there any fitment concerns or modifications required?

    I am thinking the van struts may have stiffer valving for a heavier vehicle; and therefore could be an upgrade for the cars.

    Thanks!
    David

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    Senior Member turbokinetic's Avatar
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    Well, since nobody had any info, I found out the answer for myself. The U-van struts are fully interchangeable with the A-car struts. No modifications to the vehicle were required.

    The new strut along with an old original strut. The new strut has a larger "flange" around the spring seat. The actual spring seat is the same and the springs sit on the seat perfectly.


    The rod is exactly the same diameter (I did measure with caliper!). The van strut rod is about 0.250" shorter. This could be a difference in manufacturing tolerances and not something intentional. It won't make a difference.


    The threaded rod tip is the same length and diameter. The van strut has a course thread rod, whereas the original one from the car has a finer thread. This once again could be a manufacturer's variation.


    The van strut (top) installed on the spring.



    So; how does it ride with these installed? It rides very precisely. The original front struts were not "shot" by any means. Changing to the van spec struts firmed up the ride when going over wavy roads. There is much less up and down bouncing and greater cornering control.

    I have been fighting a wheel vibration in this car for quite a while and wanted to have a fully fresh start. So, I changed all 4 shocks / struts; found and replaced one worn ball joint, and finally took the car to a performance suspension shop and had them check it out. I told them exactly what had been happening with the other tire place where I had been going. They used a Hunter Road Force machine to check the tires. This machine found two tires which were separating internally and were not "round" anymore.

    Four new tires, align and balance - and the car rides like brand new!

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    Senior Member CorvairGeek's Avatar
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    The spring base of the U strut sure looks a lot like the old Gabriel brand struts I had on the '96 Custom for years (they were for car, not van). The was only room to slide you fingers (and I don't have big hands) between base and the edge of the P205/70R14. There was/is more room between the OEM and the current Moog quick struts on the car now.

    I still have the complete assemblies, I should get a picture (and measure the anti-vibration reinforcement on the the '96 - another thread).
    Jerry

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    Senior Member turbokinetic's Avatar
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    Interesting. I do remember a long time ago I got Gabriel struts for my 86 Century T-Type. They had a similar large flange. It hit the tires and I had to cut it off with plasma torch. These seem to have plenty of tire clearance. I don't know if the Monroe struts have the flange higher up or what's the difference.

    I looked at both the Monroe "car" and Monroe "van" struts and they both had the same flange on them. I don't know what the brand of the old struts removed from my car were. I am partial to the Sensa-Track Monroe struts, so they may be earlier model Sense-Tracks.

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    Senior Member Duke George V's Avatar
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    Seems to me that the difference on the flange is that the vans use a taller tire than the cars—205/70-15 versus 195/75-14. (Or 185 on earlier cars.)

    So to adapt these for the cars you just swap the springs and hats? Seems simple enough. Might end up doing that for my white wagon, since I plan on using it as the workhorse of my fleet, and going whole hog would be best. I already have a van sway bar, and plan to put on van brakes.

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    Senior Member turbokinetic's Avatar
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    Quote Originally Posted by Duke George V View Post
    Seems to me that the difference on the flange is that the vans use a taller tire than the cars—205/70-15 versus 195/75-14. (Or 185 on earlier cars.)

    So to adapt these for the cars you just swap the springs and hats? Seems simple enough. Might end up doing that for my white wagon, since I plan on using it as the workhorse of my fleet, and going whole hog would be best. I already have a van sway bar, and plan to put on van brakes.
    That is correct. I used the van strut; with all other parts from the car. The spring seat height from the knuckle mount holes was the same. Not sure what you're calling the "hat" though. My car being an old 1984 may not have that.

    The only van part was the strut. The knuckle, spring, upper spring seat, spring isolator rubber, and strut mount (upper bearing) came from the car.

    I debated about torching off the extra material and making the new strut match the old one, but after a test-fit (no spring) revealed the tire wouldn't hit the strut - I just put them in as-is.

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    Senior Member Duke George V's Avatar
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    Quote Originally Posted by turbokinetic View Post
    Not sure what you're calling the "hat" though.
    Sorry. "Hat" is a shorthand I've heard on other automotive forums for the "upper spring seat, spring isolator rubber, and strut mount". "Top hat" is another version.

    Would you consider it difficult to assemble all the parts? I've always heard it's kind of dangerous handling the spring, since it holds so much potential energy. If the compressor pops off, one could be gravely injured.

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    Senior Member turbokinetic's Avatar
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    Quote Originally Posted by Duke George V View Post
    Sorry. "Hat" is a shorthand I've heard on other automotive forums for the "upper spring seat, spring isolator rubber, and strut mount". "Top hat" is another version.
    No problem. Just not heard that before!

    Would you consider it difficult to assemble all the parts? I've always heard it's kind of dangerous handling the spring, since it holds so much potential energy. If the compressor pops off, one could be gravely injured.
    It is not hard at all, assuming you have the proper tools.

    If you look at the last picture on the right, you can see the pair of compressor clamps, and the swivel 19mm socket on the impact wrench. The compressor clamps will do the job safely if you are careful. There are basic precautions to take; most of which are common sense.

    1 - Don't try it if you don't have the proper tools. Don't try to rig a compressor or remove the strut rod nut without a compressor in place. (people have actually been this stupid and paid the price.)

    2 - Never stand the strut on end during rod nut removal or without the rod nut installed. Keep the assembly horizontal at all times. This will mitigate the possible damage if the spring is released. The parts will be propelled along the ground and not up towards your upper body / head.

    3 - Don't try to adjust the compressor without a strut installed and the nut tightened.
    A -The compressor will not extend far enough to fully release the spring without a strut to constrain it. You will end up with the spring partially released, and the compressor jammed or cocked and can't safely release or re-compress it.
    B -Make sure the spring is fully compressed and has ample clearance before removing the rod nut. This is wise because sometimes the new strut is slightly shorter, or the new rubbers are slightly thicker. If the spring is "barely" compressed enough to get the old strut out, it may not be possible to start the rod nut on the new one. Accidents have happened when someone needed to compress the spring "just a little more" to get the nut started on the new strut. Don't try to adjust the compressor at all while the spring is not contained by a strut with the rod nut tightened. If the new strut is shorter and you can't start the rod nut, place the old strut back in the spring and install the rod nut before compressing the spring further.

    These rules are based on what I was taught at safety training classes, as well as on instructions included with the strut compressor.

    Sincerely,
    David

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    Senior Member Century7667's Avatar
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    Quote Originally Posted by turbokinetic View Post
    No problem. Just not heard that before!



    It is not hard at all, assuming you have the proper tools.

    If you look at the last picture on the right, you can see the pair of compressor clamps, and the swivel 19mm socket on the impact wrench. The compressor clamps will do the job safely if you are careful. There are basic precautions to take; most of which are common sense.

    1 - Don't try it if you don't have the proper tools. Don't try to rig a compressor or remove the strut rod nut without a compressor in place. (people have actually been this stupid and paid the price.)

    2 - Never stand the strut on end during rod nut removal or without the rod nut installed. Keep the assembly horizontal at all times. This will mitigate the possible damage if the spring is released. The parts will be propelled along the ground and not up towards your upper body / head.

    3 - Don't try to adjust the compressor without a strut installed and the nut tightened.
    A -The compressor will not extend far enough to fully release the spring without a strut to constrain it. You will end up with the spring partially released, and the compressor jammed or cocked and can't safely release or re-compress it.
    B -Make sure the spring is fully compressed and has ample clearance before removing the rod nut. This is wise because sometimes the new strut is slightly shorter, or the new rubbers are slightly thicker. If the spring is "barely" compressed enough to get the old strut out, it may not be possible to start the rod nut on the new one. Accidents have happened when someone needed to compress the spring "just a little more" to get the nut started on the new strut. Don't try to adjust the compressor at all while the spring is not contained by a strut with the rod nut tightened. If the new strut is shorter and you can't start the rod nut, place the old strut back in the spring and install the rod nut before compressing the spring further.

    These rules are based on what I was taught at safety training classes, as well as on instructions included with the strut compressor.

    Sincerely,
    David
    I might also add: Get a quality spring compressor. I got one from Horror Freight, and it was just dangerous to use. I ended up getting a quality unit with square threads and hooks that were more secure.

    Ken T.

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    Senior Member kamali's Avatar
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    David, thanks for all these great infos ..i was looking for

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    David that is really cool to see.. What size tires can you run on the A Body Sedan?

    I wish there was a better set up for the van.. The stock tires on my van were 205/70 R15... The current tires are 225/60 R16.. I have actually run the 225's with a tad bit of rub at full lock.. I have been thinking of looking for a 225/55 R16 to shorten the sidewall to get the tread a little further away from the strut... In the past I have run the van with 235/60 R16's with a 10mm spacer and longer studs, I don't really like the spacers..

    I may most likely run a new set of H or W rated 225/60 16's and possibly a 5-6 mm spacer.. I can get away without the spacer but its a hair closer to the strut than I like..

    I also managed to find a set of Monroe Reflex struts for the van, I will put those on in the near future.. I am hoping that they will add a litter more stiffness to the front end.

    I used a set of Moog Aftermarket springs at one point and noticed the coils seemed a little wider than the stock coil spring.. In the end this caused some problems with the spring rubbing on the strut tower.. I had to go back and find a set of stock springs from a 96 van and install them.. This corrected any issue I had with the spring rub, So be careful with the aftermarket replacement springs.

    Anyone looking to do a set of struts, do not buy the Cheapie Harbor Freight spring compressors unless you have a death wish.. I actually have a couple sets of Craftsman spring compressors that I use.. I have had the cheapies fail in a bad way sending the " Hat " a good 100 ft off in the distance.. Good thing I never wrap my hands around the spring and always face the hat away from me.. Dealing with struts and springs can become dangerous due to the forces at work..
    Last edited by Jr's3800; 10-31-2015 at 09:54 PM.

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    Senior Member Keiths1976's Avatar
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    Jr. I run 205 65 15 on my 95 century . Correct me if I'm wrong but I though the 14inch times can run 205 70 14 . I know with my a-body sedan it's not tight up there with what I am running and no rubbing

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    Senior Member Duke George V's Avatar
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    I've run as large as 225-50-16 on Lumina wheels on my old Celebrity, and it never rubbed. I currently am running 205-65-15 on my Century wagon and only rub one direction, hard over to the left, but that's probably more to do with the fact that the struts are worn out and it needs an alignment.

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    If anyone was thinking about this upgrade, the Monroe Reflex (p/n 71820) is on wholesale discount at RockAuto for $19.40 each. I ordered two.

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    Senior Member Old Gold's Avatar
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    Fantastic info David and thanks for the info and great tutorial! As far as proper tools, just as you said, I _highly_ recommend a set of spring compressors exactly like the ones that David recommends and that he shows in his photographs:

    http://www.amazon.com/gp/product/B00...dp_o_pd_nS_ttl

    The above link is just one specific brand, but many different brands are available that look similar. As a long-time crew chief of a grassroots production-stock off-road race team in Mexico and stuck with production style struts and springs by necessity, I generally do about 6-10 strut/spring changes per 4 day race when individual struts expire from being overheated and the oil becoming aerated... At the start of this adventure 4 years ago, we had ratchets, sockets, extensions and "hook-style" spring compressors. While they worked, they were (IMHO) total death-traps and even using careful practices, I never trusted them. The following year we switched to the style of spring compressor David mentions (along with electric impact guns of varying sizes) with solid, properly shaped spring cradles and latching pins, and the difference is amazing.

    The right tools here, as David mentioned, could save your life and are worth $30-50. If you don't want to buy them, most autoparts stores rent them for a deposit which is returned when you bring the tools back. Totally worth it!
    1985 Chevy Celebrity Sedan (2.8-X, THM125, JA2, F41)
    1954 Chevy 3100 Pickup (235 I-6, SM420)
    1994 Toyota Camry LE Coupe (2.2, A140)

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