• Hi Guest!
    If you appreciate British Car Forum and our 25 years of supporting British car enthusiasts with technical and anicdotal information, collected from our thousands of great members, please support us with a low-cost subscription. You can become a supporting member for less than the dues of most car clubs.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Which way to compress front springs?

Share this page

1

100DashSix

Jedi Trainee
Country flag
Offline
I need to refresh the front end on my MG, as the kingpins have excessive wear. I'm at the point where I'm going to compress the front springs with a hydraulic floor jack. There seem to be two ways to do this:

1. Haynes recommends putting a block of wood on the jack and pumping the spring up a bit, then unbolting the spring pan from the a-arms. You then lower the jack slowly and the pan and spring come down.

2. Art Pfenninger describes a different method over at MGExperience.net. He says to jack the spring pan up and disconnect the swivel axle from the shock absorber by tapping out the fulcrum pin. The a-arm and pan assembly would then be free to swing down, in an arc. (Couldn't this slip on the jack?)

Which is better? I would like to avoid killing myself during this job.
Thanks.
 
Either way can slip on the jack. How about this one... use a spring compressor. The right tool for the job, and the best $40 you can spend when it comes to springs and safety.
 
NAPA sells one for $52. Strangely, Advance Auto rents one for the same price.

Say I used a spring compressor instead of a jack (or some combination of the two).. Should I tap out the fulcrum pin or disconnect the spring pan from the a-arms?
 
Either way works just fine, really. If you remove the top bolt, make sure the king pin / hub assembly doesn't swing down and hit the floor, or worse yet your knee!
 
I have used a jack and removed the pin...easier than trying to get at the pan bolts. Probably safer, too, as it limits time and torquing under the car. Use good jack stands...and just to be sure, loop a chain or heavy cable around the spring before you lower the arm to prevent the spring from slipping and popping out into your face.

Bruce
 
Neither way.

Remove the bottom trunion bolt with the jack under the spring pan and then lower the jack. If the spring does see fit to sproing out, it is covered by the upright and shouldn't be able to escape and cause damage. Once you have lowered the pan as much as possible, you should be able to urge the spring out of there with prybar or screwdriver - if it is under any tension it isn't much.

Going back in, you can usually offer the top of the spring up first and then once it is seated use the prybar again to get the lower rear lip of the spring back over the seat in the lower pan, at which point it will be holding the pan firmly down as far as it will go. Raise it with the jack until you can slip the lower trunion bolt home.

If you are using a stock spring there will be a bit of tension left at the bottom of travel when you are removing it, but if you have a stiffer shorter version it will be loose by the time the pan hitsthe lowest point.
 
Steve_S said:
Either way can slip on the jack. How about this one... use a spring compressor. The right tool for the job, and the best $40 you can spend when it comes to springs and safety.
Click to expand...
Tell me where you got a spring compressor small enough to compress the springs on an MG?

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]NAPA sells one for $52. Strangely, Advance Auto rents one for the same price. [/QUOTE]
Neither of those will work - I've tried both!


Springs on an MGB or Midget can't jump out of their housings to hurt you - trust me on that one - with a floor jack under them! I usually drop the entire suspension beam intact & break it apart on the tailgate of my old Sonoma (did one yesterday)....I'll remove the kingpin from the shock & push it aside with the spring in place....all it does is push the lower assembly down a little....& I don't even try to encapsulate or trap the spring...it just goes 'sproing' & pops a little but won't jump out or throw things!

Put a block of wood under the spring perch & jack it up until the spring is in a place where you can remove or install the shock to the kingpin...then lower the jack....I've done that on hundreds of MGB's & never had a problem!

(& I've got every spring compressor I could buy & a copy of the factory tool that I had made....none of the store bought compressors I've bought will work & the factory copy I made is a pain in the butt to use!)
 
Thanks for the advice. I wrapped a chain twice around the spring and pan and used the jack method. It was simple to drop it, and I just did it methodically and slowly.

I have jobs ahead of me, though. It feels like the lower trunnion bolt has fused to the distance tube or bushing. The pin can't be knocked out or broken free (so far). This is all very familiar.. I had to cut the bolts when I replaced my rear leaf springs. There's also play in the wishbone arms against this pin...it probably wallowed out a bigger hole.

Rotating the wishbone and spring pan assembly on its pivot is surprisingly difficult. I thought it would flop down, but there's lots of resistance. Could this be due to more worn/fused bushings on the pivot?
 
tony barnhill said:
Tell me where you got a spring compressor small enough to compress the springs on an MG?
Click to expand...
All Car Parts
21407 Vanowen St
Canoga Park, CA 91303

Or you can buy one from Mac Tools. Grind off 1/8" from the main bracket and it slips up into the spring with a twisting effort.
 
Got a photo of it & a parts number....though I don't know why I asked...I just stripped the shocks off another crossmember on my truck tailgate without worrying about the springs going anywhere!
 
I picked it up off the shelf. No idea what they part number would be, but it's a US-made tool and it's black. Search Mac tools for spring compressors. It looks exactly like the one they sell.
 
100DashSix said:
Rotating the wishbone and spring pan assembly on its pivot is surprisingly difficult. I thought it would flop down, but there's lots of resistance. Could this be due to more worn/fused bushings on the pivot?
Click to expand...

Yup...sounds like it is time to replace the wishbone arms, so get a new bolt and bushings while you are at it.
 
Front suspension rebuild

After an hour of sanding one side of the wishbone pivot looks like this:
wishbone_pivot.jpg


That's rust and crud worked into pits in the metal. Is it good enough to reuse?

Here's another good one...check out this hole in the wishbone arm!
wishbone_hole.jpg


I wonder what my car will feel like when this is all done.
 
Re: Front suspension rebuild

If your new bushings are poly, and worth their weight, they will have a stainless inner sleeve which fits over the pivot. This makes pitted metal on the pivot a non-issue.

If your new bushings are rubber then you may be ok. If they are poly with no sleeve then I'd be concerned.

Also, repair or replace that arm. You don't want to run that thing another mile!
 
Re: Front suspension rebuild

Yeah, I plan on getting a poly bush kit from one of the usual places, and replacing all the bushings I have access to now, as well as the anti-sway bar bushings. Heh. I have no plan on reusing the wishbone arms, now that I've seen how bad they are. I'll have to get them with the sway bar link, too.

More pictures to come as I have fun with this project! Rubberized undercoating makes things look awesome.
 
Re: Front suspension rebuild

That elongated hole is the reason for the play that you referred to earlier...and needs replaced for sure. The pin might not slip into a steel liner like that. You may need to grind some of the high points off, or have a machine shop smooth it off for you in order to get the metal sleeved bushing on to it. If you do smooth that pin, I have a set of steel lined V-8 bushings you can have for the postage.
 
Re: Front suspension rebuild

Yep, you either need new wishbone arms or a good, used set of arms....lemme know if I can be of help - I have both.
 
Steve_S said:
tony barnhill said:
Tell me where you got a spring compressor small enough to compress the springs on an MG?
Click to expand...
All Car Parts
21407 Vanowen St
Canoga Park, CA 91303

Or you can buy one from Mac Tools. Grind off 1/8" from the main bracket and it slips up into the spring with a twisting effort.
Click to expand...

That's what I did and it works great! It's much smaller than the standard spring compressor. And, no worries of anything popping out in your face, or elseware. I wind mine up with an angle drive air ratchet.
 
I just don't see the need for one!
 
Agree with Tony here. I always undo the lower pivot bolt/whatever you want to call it; the closest to the tire, on the narrow end of the control arm assembly, and let ot down with a trolley jack. Never a problem, probably done it a dozen times. Spring simply falls out, no energy left in the spring.

Colin
 
Back
Top