4cv/Dauphine kingpin wear

[Stan W]

Despite the fact that my 4cv has only 28.000 miles, the kingpins are worn. The wear appears to be mostly in the top bushings. Rarely greased I guess. I measured the wear with a dial indicator. The left side moves about .003" at the top, the right side moves .005" at the same spot. That translates into a lot more movement at the top of the tire. I don't think the rubber bushings are very worn, but I cannot see the ones at the top and bottom of the kingpin assembly.

Is the problem likely to be fixed by installing new bushings or will the kingpin itself be worn?

 

[JohnW]

Despite the fact that my 4cv has only 28.000 miles, the kingpins are worn. The wear appears to be mostly in the top bushings. Rarely greased I guess. I measured the wear with a dial indicator. The left side moves about .003" at the top, the right side moves .005" at the same spot. That translates into a lot more movement at the top of the tire. I don't think the rubber bushings are very worn, but I cannot see the ones at the top and bottom of the kingpin assembly.

Is the problem likely to be fixed by installing new bushings or will the kingpin itself be worn?

Have to pull it apart and see I'm afraid. I have seen factory steel bushes (Steel???? Yes....) as well as bronze ones and distinct wear on the kingpins themselves. My approach would be to pull it apart and get new bronze bushes machined to suit the kingpins. You might need to machine down the middle part of the kingpin(s) to get the top bush on. My custom machined bushes are perfect after 30 years of regular greasing. I reckon there's a good chance of not needing new kingpins.

 

[Stan W]

Someone in the USA has most of the rubber bushings and the kingpin bushings they would like to sell. I was trying to decide whether or not to buy them. I guess the answer is "maybe". The new bushings should be a little smaller in diameter than the kingpin (reaming required). I don't think any of the rubber bushings need to be replaced, Do the rubber bushings on the top and bottom of the kingpin wear faster than the others? My car appears to have a slight bit of negative camber at the front, but I think that is due to the wear in the kingpin bushings.

 

[JohnW]

Someone in the USA has most of the rubber bushings and the kingpin bushings they would like to sell. I was trying to decide whether or not to buy them. I guess the answer is "maybe". The new bushings should be a little smaller in diameter than the kingpin (reaming required). I don't think any of the rubber bushings need to be replaced, Do the rubber bushings on the top and bottom of the kingpin wear faster than the others? My car appears to have a slight bit of negative camber at the front, but I think that is due to the wear in the kingpin bushings.

I don't know either answer to be honest. They are Silentbloc bushes, so don't wear but suffer degradation and deformation of the rubber eventually. I think that in turn is exacerbated by the amount of suspension movement that there has been - bad road driving and/or overloaded boot.

My 4CV has steel screw bushes not rubber ones and the R8 has balljoints. The R8 lower wishbone bushes have been replaced at comparatively high mileages twice in 350,000 km. So they've lasted quite well I reckon. The upper wishbone bushes have only been replaced once and hte current ones have done about 100,000 km. The Dauphine ones look similar to me and I guess it is slightly lighter.

 

[Stan W]

It turns out that I don't need to be concerned with the kingpin wear. The parts for sale here in the US were a set of new kingpins and bushings. I seem to remember that original bushings had a spiral groove to allow grease to flow the entire length of the bushing. The new ones have a single groove around the middle. On any car I have owned with kingpins, I took the weight (and spring force) off the kinpin when greasing. Will these new kingpin bushings work just as well as originals?

 

[JohnW]

Well, well the real thing! I doubt very much that you'll experience wear in your lifetime! Ditto here re unloading before greasing - I guess it opens the top and bottom gaps so grease flows properly and lubricates those sliding surfaces.

 

[Stan W]

I am considering taking the upper and lower A-arms off my 4cv while the kingpins are getting machined. The reason to take them off is to paint them, I don't need to replace the rubber bushings. Will I change the castor angle by removing and reinstalling the A-arms, or do the bolts keep them in the correct position? I was thinking of removing the four bolts on the lower arm and the three bolts on the top arm - not planning to loosen the large bolts that go through the rubber bushings.

 

[JohnW]

Caster isn't adjustable and yes, the small vertical bolts hold it and set it. Good the Silentbloc bushes are OK - I've changed mine on the R8 twice now (driven continuously for 58 years mind you) and have got them out with careful pressing with big bolts, socket spanners and washers etc and and in with the vise to replace them. There are plenty of stories out there about remanufactured rubber products so if the originals are good, that's great.

Definitely don't touch the long bolts if you don't need to as they have setexactly the correct position regarding the suspension position. If that moves, you can over-shear the rubber bushes and then they fail. When I did the R8 the first time I got that wrong and they failed just 15 years and about 100,000 km later. Should have lasted much longer. This last time I loaded the boot to mimic two passengers before I tightened the nuts. I have another set of NOS spare bushes.

 

[Andrew Watkins]

Caster isn't adjustable and yes, the small vertical bolts hold it and set it. Good the Silentbloc bushes are OK - I've changed mine on the R8 twice now (driven continuously for 58 years mind you) and have got them out with careful pressing with big bolts, socket spanners and washers etc and and in with the vise to replace them. There are plenty of stories out there about remanufactured rubber products so if the originals are good, that's great.

Definitely don't touch the long bolts if you don't need to as they have setexactly the correct position regarding the suspension position. If that moves, you can over-shear the rubber bushes and then they fail. When I did the R8 the first time I got that wrong and they failed just 15 years and about 100,000 km later. Should have lasted much longer. This last time I loaded the boot to mimic two passengers before I tightened the nuts. I have another set of NOS spare bushes.

You can fit two bodies in your boot?

Shall remember that next time I have an unwanted business competitor

Andrew

 

[JohnW]

You can fit two bodies in your boot?

Shall remember that next time I have an unwanted business competitor

Andrew

ROFL

"....to mimic".... I think it was 40 kg of cement, the passengers being a fair way back towards the rear suspension load point. If you need to shift bodies, better to find a good R10 as the boot is much larger.

 

[Stan W]

Caster isn't adjustable and yes, the small vertical bolts hold it and set it. Good the Silentbloc bushes are OK - I've changed mine on the R8 twice now (driven continuously for 58 years mind you) and have got them out with careful pressing with big bolts, socket spanners and washers etc and and in with the vise to replace them. There are plenty of stories out there about remanufactured rubber products so if the originals are good, that's great.

Definitely don't touch the long bolts if you don't need to as they have setexactly the correct position regarding the suspension position. If that moves, you can over-shear the rubber bushes and then they fail. When I did the R8 the first time I got that wrong and they failed just 15 years and about 100,000 km later. Should have lasted much longer. This last time I loaded the boot to mimic two passengers before I tightened the nuts. I have another set of NOS spare bushes.

Thanks John! I have put "modern style" bushings in two MGAs and understand the requirement of tightening with the car properly loaded. The "modern style" upgraded bushings on the MGA were the type used on my 4cv. The kingpin set I have did not include new thrust washers/bearings, so I may need to add more shims on reassembly.

Just out of curiosity, will R8 front suspension A-arms bolt to the 4cv, or does the entire front crossmember need to be replaced to use R8 parts?

 

[JohnW]

Pleasure. To the second question, it is the whole cross-member to use R8 suspension parts. But you can fit the disc brakes to the 4CV stub axle assemblies with early R8 hubs or R10 hubs machined to get the bearing separation correct.

Regarding thrust washers, do you mean the top, curved washers? Shims go at the bottom to get end clearance correct.

Your MGA had screw bush suspension originally? Like my 4CV?

 

[Stan W]

I don't have new seals for the top of the kinpin. I don't really want to order one small part from France and was wondering if anyone had used something else for a seal. I could use the boot from a brake wheel cylinder kit - tried one I have around, but need something bigger than parts from a 22 mm cylinder.

John, The MGA had rubber bushings, but without the metal. The MGB V8 used bushings with a center metal tube (but not an outer metal piece). The MGB V8 bushings are much better and most people use these in their MGAs and MGBs. There are washers that supposedly squash the rubber sufficiently to keep it from moving in the A-arm. The silentbloc bushings on the 4cv are probably better, but harder to install.

 

[Stan W]

I don't have new curved washers at the top. I suspect they have some wear which might cause more end play in the kingpin (more shims required).

The MGA did have screw/bush assemblies instead of a regular kingpin. They never wore out if greased properly. They were never greased properly

 

[JohnW]

I don't have new curved washers at the top. I suspect they have some wear which might cause more end play in the kingpin (more shims required).

The MGA did have screw/bush assemblies instead of a regular kingpin. They never wore out if greased properly. They were never greased properly

View attachment 213301

I didn't know there WERE seals at the top klngpin pivot for at least 20 years of ownership, until I bought a factory repair kit. For casual use, providing they are greased regularly, I don't think it is a big issue. Polish the top of the sub axle assembly where the curved washer slides, and the top of the kingpin where it bears against the curve of the washer. The "seals" have an internal wide groove that helps them stay in place, so rubber, like a pinchweld section cut down and glued into a circle with superglue, would be worth trying. I'd struggle with $50 postage for two $1.50 bits of rubber too!

Yes, screw bushes seem to last forever if greased. If...... Mine were worn almost flat on one side when I bought the 4CV in 1966, but the replacements are still quite tight, greased every thousand km or more frequently. I'm nearly paranoid about it!

What you describe for the MGB V8 sounds really odd - in Europe there is a type of bush called "Fluidbloc", with a centre steel metal tube but no outer tube BUT the rubber has a grease-retaining profile and rotates inside the outer metal into which it is pushed. Some Citroen bushes are like that, and the upper wishbone bushes on R8/10 series cars. Porsche reportedly planned to use them on the 911 but decided against it on grounds of durability. I think I'd agree with them although I've only had to replace mine once.

Your description suggests the MG bush is designed to shear, not rotate, but without the rubber being bonded to an outer steel tube. "Neither fish nor fowl nor good red herring" comes to mind. They must be an extremely tight fit to work I suppose.

 

[Stan W]

I finally got around to having the kinpins fixed. The machine shop owner liked the original kingpins better than the new ones. The originals were not worn (only bushings worn) and the surface of the new ones was not quite as even and smooth. The new rubber bushings were pushed out of the new kinpins and installed in the originals. The kingpins are now nice and tight, but turn easily. I had to make a shim, but eventually got the end play on both kingpins around .001 - .002". The most difficult part of the project was cleaning and painting the front suspension and painting the area around the steering rack. That was the only part of the car I had not gone over. I removed the steering rack to replace all the old grease. It didn't look bad, but new grease is good! I haven't tried the car at 75mph yet, but I am sure it is better than before . I have included a picture of the tools made to install the various bushings.

While the spindles were off, I had the brake backing plate bolt area faced so that the bolts are not twisted when tightened. I had a number of appropriate high strength metric bolts in my extra hardware box.

 

[JohnW]

I finally got around to having the kinpins fixed. The machine shop owner liked the original kingpins better than the new ones. The originals were not worn (only bushings worn) and the surface of the new ones was not quite as even and smooth. The new rubber bushings were pushed out of the new kinpins and installed in the originals. The kingpins are now nice and tight, but turn easily. I had to make a shim, but eventually got the end play on both kingpins around .001 - .002". The most difficult part of the project was cleaning and painting the front suspension and painting the area around the steering rack. That was the only part of the car I had not gone over. I removed the steering rack to replace all the old grease. It didn't look bad, but new grease is good! I haven't tried the car at 75mph yet, but I am sure it is better than before . I have included a picture of the tools made to install the various bushings.

While the spindles were off, I had the brake backing plate bolt area faced so that the bolts are not twisted when tightened. I had a number of appropriate high strength metric bolts in my extra hardware box.

View attachment 215996View attachment 215997View attachment 215998View attachment 215999View attachment 216000View attachment 216001View attachment 216002View attachment 216003View attachment 216004View attachment 216005

Nice work. Your tools for the Silentbloc bushes are more sophisticated than mine! Great you could use the original kingpins - they've proved their quality! Some of us have disabled that return spring in the steering rack - there's plenty of self centering without it. Easily done by pulling off the cover and knocking out the circlips.

 

[Stan W]

It was amazing watching him make the silentbloc tool, it was done in two minutes. The return springs have never bothered me. I think they help when making very sharp turns on the golf cart path. It has been very wet here, so the golf course is a sea of mud. That doesn't mean I don't try to play! The 4cv has been staying on the cart path, but still needs the bottom rinsed every time it goes around the golf course (puddles in the paths).

I am getting ready to put a timing belt (and all associated parts) on my Volvo C30 with the T5 engine. It makes me appreciate the simplicity of the 4cv.

 

[JohnW]

It was amazing watching him make the silentbloc tool, it was done in two minutes. The return springs have never bothered me. I think they help when making very sharp turns on the golf cart path. It has been very wet here, so the golf course is a sea of mud. That doesn't mean I don't try to play! The 4cv has been staying on the cart path, but still needs the bottom rinsed every time it goes around the golf course (puddles in the paths).

I am getting ready to put a timing belt (and all associated parts) on my Volvo C30 with the T5 engine. It makes me appreciate the simplicity of the 4cv.

I've always wanted a lathe but know I'll never do enough to become proficient! I've pullled and/or pressed all mine in and out with a combination of socket spanners, threaded pipe fittings, washers of various sizes, long bolts and sometimes old bush outers themselves. The photo is pulling out a lower wishbone bush on the R8. I've made up tools out of hardwood for the differential carrier bearings!

I've also chickened out on cambelt changes - so right about the simplicity. Good luck.

 

[Stan W]

I've always wanted a lathe but know I'll never do enough to become proficient! I've pullled and/or pressed all mine in and out with a combination of socket spanners, threaded pipe fittings, washers of various sizes, long bolts and sometimes old bush outers themselves. The photo is pulling out a lower wishbone bush on the R8. I've made up tools out of hardwood for the differential carrier bearings!

I've also chickened out on cambelt changes - so right about the simplicity. Good luck.

Thanks for that picture, I will eventually replace the wishbone bushings even though they still look fine. Got the Volvo timing belt done - no major problems, but not as much fun as working on the 4cv.