If this were me, I'd have looked into your last option first i.e. a stainless steel plate on top and bottom of, and bolted across the axle/chassis and new indespension units bolted on. Are you sure the inside of the axle is well galvanised and not going to burst?
FWIW our 3 ton boat was towed from N. Wales to Southampton on its trailer one day last weekend. The trip went extremely well.
PS if anyone near Wirral wants a GP14 as a big project, I'm hoping to pull it out of our front "hedge" on its trailer sometime soon. We are in a smoke free zone, so it will probably have to be freecycled.
True, however, there does seem to be quite a bit of damping in the basic rubber / torsion suspension as I rarely see one oscillating on the road, even at speed. In fact I've seen many un damped car wheels and wonder why MOT's don't check them? [1]
Not all boats are heavy, the one I towed the other day was actually designed to be roof topable at 75kg, so attached or otherwise it would be the lack of suspension travel and compliance that would cause it to 'jump' (because of a bump or hole etc, not on it's own and never with any oscillation).
True, but not because of poor / no damping but because of under compliant suspension and / or a massive difference between the loaded and unloaded weight (or as you say, 'light objects' = no real load).
As mentioned elsewhere, the trailer I tow behind my motorbike has very light suspension because the maximum load is only the same as the weight of the trailer and that's mostly limited by the weight of the towing vehicle itself. Because it doesn't use any torsion but just rubber in compression, it does have dampers to keep things under control.
The 1/2 tonne trailer I built over 40 years ago has MM wheels (on Indespension units) and is reasonably heavy itself and so is fairly well behaved even when empty. Similar with the little steel framed with wooden panels trailer I made for my BIL (that even has a drop down tailgate and wheels allowing it to be rolled when stood on it's end, so it can be rolled sideways down a narrow side access. ;-)
The BOB Yak trailer that we tow behind the cycles doesn't have any suspension at all and will only bounce with any sort of load in it when it hits a rock. ;-)
We currently have 10 trailers but we do need to sell some. ;-)
I was assuming it would be pretty straight as I'd be freezing it whilst stretched? ;-)
Again, I was hoping the reduction in diameter caused by the stretching would be enough that it would drop in? If it didn't I'm not sure it would work?
I think I'd be slightly worried about using any lubricant as 1) I was hoping I wouldn't have to and 2) the consequences of it staying there or reacting somehow afterwards
In my head it would be something like:
Cut the 4 cords to length plus a bit (to grip whilst stretching) with some thread on one end of each so I can dangle them in the axle.
Put the stub axle in the domestic freezer.
Stand the end of the axle tube in some LN to get that as cold as possible.
Put the stretched rubber cords in the LN and leave long enough so they freeze right through.
Stand the axle cold end up, lower the 4 cords into the 4 corners and then insert the stub axle assy (where hopefully it will just slide in with minimal contact with anything) and set it with the right end gap.
Hmm, if you are talking a straight 'sandwich' mount here I'm not sure if it would keep good alignment (SS being quite slippery n all) or certainly without it being some sort of channel or even having an angle between the suspension unit and chassis tube to maintain some sort of trans alignment (tracking etc).
OOI, the axle tube is 40 x 40 box and could be 3+mm thick (I can't easily get to the end of it but will try tomorrow). The hole centres across the axle are 79mm so if using an M8 bolt with a 13mm AF nut that leaves:
79 - 40 -2 x 6.5 (half 13) = 26mm (13mm each side) of play room between the nuts and the axle. So, If I was to weld two lengths of 40 x 40 x even 3mm angle on top of the mounting plate (to form two guides or a channel running front and back of the axle) and then bolting them (so interference fit 'shouldered bolts') though and also a couple of countersunk screws up from underneath the plate and into a strip with captive nuts inside the axle tube at each end, that should give me something rigid and stable to bolt the suspension to and wouldn't need any welding and I could even get hot galvanised before fitting (as long as I allow for it etc. Or even one heaver strip on the front (then I won't have to allow for the galv) as because the wheel trails the axle there is only a turning moment in one direction so the strength might be best in the front where the bolts will be in tension.
Good point Bill, until I get the old rubbers and suspension boss out I won't be able to tell.
Excellent (I bet it was still a relief when you got home though)?
We towed the Leisure 17 from Sth Wales to Nth London and that was a twin bilge keep jobby so standing fairly high ... whilst not having much weight in the keels. ;-(
Hmm, 14' trailer you say ... ;-)
I wonder if the club I gave the 14' Skipper to recently needs 'project boats' for any of their school groups?
I'd happily come and get it if the trailer was good enough to get it and the boat back home safely?
Ours is one long keel on top of the iron casting, so it's the adjustable props that were my worry, but they were OK. I only did part of the journey, son did the rest in a Transit.
It's not worth coming any distance for, I'm afraid. The trailer is just two galvanised scaffold poles in a V shape with an axle bolted across at the appropriate place. The tyres are flat. The piggy-back launching trolley is a smaller axle that takes a U-shaped piece of conduit as its "handle". The conduit has rusted away, of course. All very primitive, but it always worked very well.
The GP itself is in a bad way, as the cover fell apart some years ago and it has been open to the weather. The mast prop has gone through the bottom, and I don't know whether it is just through the plywood or more structural parts. It's in a very deep holly hedge which is why I can't get at it easily.
Having said all that, it's probably only back to the state it was in when we were given it almost 40 years ago. We still have photos of very young son standing through the bottom of the upside down hull.
Ideally, I'd like it to go to someone locally who wanted a challenge to take on with their children.
I have used some 'Platenclene' to revive old rubber when I was restoring a record deck. It is designed to treat printing rollers. It worked well for me.
Looking at the suspension units closer now the boat isn't on it it seems one side is worse than the other. The best one deflects a bit with my 10 stone, whereas the other looks much flatter and therefore deflects even less.
I believe this is a problem with light trailers in general (even with new suspension) with people reporting damage to fibreglass hulls caused by to 'stiff' suspension. It's ok if you boat is heavy enough to put some load on the trailer but even the lightest trailers are heavier rated than many small dinghies.
If any rejuvenation experiments don't work then I'm looking at some bonded rubber suspension units that are supposed to be more compliant and therefore 'more suitable' for boat trailers.
Cheers, T i m
Funnily ... years ago I bought a fibreglass topped 'walk-in' 1/2 tonne goods trailer that was previously bought and converted by a launderette so that they could hang and deliver washing and ironing back to their customers. However, even after adding paving slabs and other heavy objects to the floor, every journey ended with all the clothes on the floor (so they sold it and bought a van). It was fine for me with a 1/3rd of a tonne of disco gear in it. ;-)
Wooden boats can work on the 2CV principal. 1st the top leaks, then it fills up with water, then the bottom rots and it then becomes a self draining solution. ;-)
Not quite so good on the kitcar. The windscreen rubber has shrunk slightly and so now leaks in heavy rain. Foot wells are fibreglass and need bailing out now and again. ;-)
Shame.
Ouch.
;-)
Do many children have the patience for such things these days?
It was quite nice 'supervising' our daughter remove and clean the (4) carbs on her Suzuki 600 bandit today. Like me she resigns herself to accepting these things will take the time they take and trying to go faster is more likely to end with something broken or someone hurt.
The good news was after 6 hours (that included me going out and recovering my Mrs and a neighbour and her mobility scooter that just broke down a mile from home. A quick check over before throwing it and them in the car showed the electronic controller partly filled with water!) was that the bike seems to be running well again. Nothing worse than going though all that effort for no positive result (other than ticking another box in the diagnosis process and the experience etc).
I hope you do find a good home for the boat though Bill. ;-)
Today I borrowed a 4 tonne 'PortaPower' type hydraulic ram and was able to get it between the trailing arms of the independent suspension units and push them out (well, I pushed one out that way and then had to re-seat the piston on the trailer itself at one end and additionally assist the other arm out with the use of a long heavy spike used as a slide hammer inside the axle tube).
Extracting the units this way allowed me to see how they were put together and it seems there were two half-(square)-tubes that formed a clamshell over the main suspension spindle and the 4 polyurethane (so not rubber as such) 'rods' trapped in the corners.
So, it may be possible to re-equip the units with new 'rubbers', clamp the clamshell together and slide it back into the axle tube (where it will expand) and lock the clamshell parts back in place with a couple of set screws (previously it looks like it was just peened over slightly).
Or, I could re-build the units into some short box sections (the same as the axle tube) welded to some 4 / 6 hole mounting plates and bolt them onto matching plates in the traditional way, or even vertical plates allowing me to bolt the units though the axle tube, rather than having to weld to it (and spoil the galv).
Cheers, T i m
p.s. Now I just need a suitable Shore hardness meter / Durometer to work out the hardness of the original 'rubbers'. It seems there are several types?
Are you going for rubber, or polyurethane again? The problem with matching up with the old ones is that they might have hardened, or softened. Can you get new spares? You can get casting polyurethanes, probably not with much range in hardness. If you have two materials side by side, to a first approximation you can compare their properties with a thumbnail, or by squeezing with a pliers.
There are various instruments, but mostly using one of two Shore scales (A and D). I guess these may be medium to hard rubbers, probably use the Shore A scale?
"The Shore A Hardness Scale measures the hardness of flexible mold rubbers that range in hardness from very soft and flexible, to medium and somewhat flexible, to hard with almost no flexibility at all. Semi-rigid plastics can also be measured on the high end of the Shore A Scale".
Reading up on it all it looks like PU is superior to rubber in it's resistance to chemicals and perishing but in rod form (in a hardness suited to vehicle bushings) it's quite expensive (cheaper to buy new suspension units).
Good points.
Only in stock generic rod lengths AFAIK.
I spotted that and watched the Youtube video on the guy who cast his own car engine mounts.
Good idea.
I think that seems to cover the values associated with this sort of application, 1-100?
Check.
I understand that some (all?) PU is a thermo plastic and so in theory I might be able to re-melt and re-form the existing (squished) rods into new circular ones? If I was to do that, do you think the material would re-gain it's elasticity?
If I was to use the casting PU, how would I make a mold that would allow the PU to release (I could easily use some suitable 10mm OD dowel as a plug etc).
formatting link
If I was to have a go at rebuilding these units I wouldn't use them on the road unless I was very confident they were as (or more) secure as they were originally. It's fairly easy to get a rough idea of their capacity by standing or bouncing on one end of the axle and noting the sag and deflection etc. I would also fit a retainer plate across the inner end of the suspension arm to prevent it from ever coming out of it's 'shell' and screw lock the 'shell' into the chassis. Given it took a 4 tonne hydraulic press (working pretty hard) and a 5' long steel slide hammer to get them out, I'm not sure that would ever be an issue. ;-)
I think some of it at least is thermosetting. My guess is that it would be difficult to melt without burning.
All sorts of options. Use a cardboard tube with a polythene bag inside. If you can find PE or PVC tube of the right sort of diameter (cistern overflow pipe?) cast inside the tube, it may well then pull out because as you stretch the end the diameter gets smaller (cast something like this in one end to get a grip)
formatting link
$prodImageMedium$
or failing that slit the tube after casting to spring it open.
Ok, I'll give it a test in a bain-marie (as I've read suggestion of it melting at ~70 DegC).
I had thought of a few but was concerned how *it* would know I actually wanted it to bond to the inside of any mould or not (eg, if it was simply a mould or something like an engine mount)? ;-)
Unless the 'bag' was a thin (this rod is only 10mm OD remember), compliant and well fitted to the inside of the tube as cling film or maybe a long balloon, I'm not sure what sort of accuracy I would get to the inside of the mould?
Hmm, interesting idea and I'd have to mould 'extra' rod to be able to afford to do that.
'8 tubes' but yes, assuming it 'let go' of the inside of my tube then it should be ok. (I'm not sure I would want to make it in one
800mm length because of the (in)ability to pour it down that length cleanly and I may be more likely to get air bubbles trapped etc)?
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.