strange damper behavior

[dafix]

Hi, I noticed that the left front damper of my DAF 46 was stuck: nothing moved when I pushed the bonnet downward (although on the right side it behaved like a normal suspension, bouncing back to its position). Just for curiosity,  I jacked the car up and removed the gland nut of the damper. I managed to do it using adjustable pliers, but I would prefer to have the special tool described in my manual. I had a quick look inside and put the car down on its wheels and the damper was no longer stuck. Then I realized that tightening the gland nut makes the damper stiff. My hypothesis: the gland nut, when tightened, pushes the stack of washers (that had become too soft) underneath and make them gripping the rod... My questions are:

1) Has anyone of you already encountered this problem ?

2) Would it be useful to replace the washers (or other parts of the damper) ? Looking at dafhobby.nl, there are no damper parts sold and I would prefer to avoid to buy a complete damper.

3) How to procure the special gland nut tool, which apparently is also needed to remove the guiding nut located under the stack of washers ? Or which tool can be used to remove this guiding nut ? If I have to replace the washers, it would probably be a good opportunity to change the oil (I have read that 15W for motorcycle forks is OK).

I have also noticed that the bellows are very stiff and do not cover well the dampers. Perhaps some dust entered the damper, which created the problem ? Anyway I would like to replace them.

Your help is welcome

[swissdave]

Hi Dafix. I recently managed to buy a large adjustable spanner that opened wide enough to fit the gland nut so I managed without the special tool. I fitted new sealed units into mine originally but in retrospect I think a rebuild with the original components and new oil would have been better as the replacement strut inserts weren’t very good and seemed too weak, I’ve since changed them for something else.
I think the new seals and washers must be available from somewhere?
Danny at Daf Hobby has the replacement rubber bellows at a reasonable price.
With regard to the original sticking problem I wonder if the rod is bent slightly?
Regards, Steve.

[swissdave]

See this post I put up about it on Essex Dafs; essexdafs.proboards.com/thread/712/changing-front-dampers-55-66

[dafman50]

i always use aftermarket inserts .remove old parts drop in insert and tighten new nut . as they are gas unit take bumps better .

[dafman50]

i always use aftermarket inserts .remove old parts drop in insert and tighten new nut . as they are gas unit take bumps better .takes about 1hr from start to finish . currantly doing a 44 snd 66 at mine for 2 owners .

[dafix]

Hi Swissdave, thank you for your advice, I checked that post (interesting forum !). I used basically the same tool as yours to remove the top gland nut, but it seems on DAF 55/66 that the damper units have to be replaced. In my case (DAF 46), according to the manual they require maintenance (check the rod, replace the oil and small parts). Under the top nut, there is a cup (that I saw), then normally a stack of washers (to remove using a needle, according to the manual), and then another gland nut which guides the rod. I have no idea about its shape, but the manual states it has two holes on each side of the rod to allow to insert a tool into it. I am proceeding carefully and usually I prefer to dismantle something only when I am sure I have to right tool, to have the the work completed and to not leave a mess in my garage . 

[dafix]

I drove my DAF yesterday, with the top gland nut of the left strut loosened (and secured with some aluminum tape ). When I was back home, the damper was stuck again ! I removed the top nut to have a look: there were some parts stuck to the bottom of the nut that do not slide very well on the rod, also I notice an o-ring inside the strut (the green color is just due to the terrible paint job done by one of the previous owners ):



This actually looks quite different from what is described in my manual:



but close to what you swissdave showed in your post. Perhaps non-genuine dampers have been fitted. Now I am considering to buy new damper units (piston rod + tube), I see that dafhobby.nl sells them. I am not sure if they come ready to be installed (like in modern cars), or if they have to be filled with oil. It looks like that the external strut tube has to be filled, not the damper itself (but I guess the oil has then to penetrate the damper tube to create a friction between the piston and the tube)...

[dafix]

I bought new front dampers/shock-absorbers and bellows from dafhobby.nl (I got them only 3 days after I ordered them !) and installed them last week. This is how I did:

I started first with the left side because its damper had a problem (did not move up and down). The jack-and-crank holder (picture below), located over the left wheel, forced me to remove the two bolts (and their washers) of the bushing first, before removing the top castellated nut. Before doing it, I jacked up my DAF to prevent the damper from pushing upward while loosening the bolts of the bushing.





Then I could remove the safety pin and the castellated top nut. Since the damper was stuck, it was not necessary to block it by clamping its flat tip with pliers. I just put back one bolt of the bushing to prevent it from rotating. Even if the damper was stuck, I could use a hammer and a drift to push down the rod of the damper. And allthough the hole left in the inner part of the wing/fender (after the bushing is removed) is large enough to have the damper going through (see picture further), this step (pushing down the rod) remains necessary to remove the bellow from the damper.



OK, the bushing and the top cup were removed, as well as the bellow. I already loosened the gland nut of the damper (using adjustable pliers and some effort). The guide (i.e. the sleeve between the inner of the strut and the damper that protrudes from the strut when the gland nut is removed) was not threaded and could be easy taken out with the pliers. Then the damper could be easily lifted in one piece (nothing tied it to the bottom of the strut). In conclusion, this damper system was NOT the original mounting as described in the manuals. It was installed by a previous owner and is very close to what Swissdave shows in his topic in the Essex Daf forum.





There was a considerable quantity of oil that leaked from the damper. I don't know how this happened (it was also the same mess on the right damper). I was prepared to apply the procedure described in the manual for the original dampers and I had a syringe (bought for one euro in a pharmacy ) connected to a piece of hose (taken from an old washing machine water supply hose). This helped me to pump out the oil remaining in the bottom of the strut, but I could not remove all the oil.



The new damper (I noticed they are made in France. Strange to import back to France items that were exported to the Netherlands, well this is EU !) was inserted into the strut (just left it loose at the bottom of the strut), from the hole in the wing . I then tightened the new gland nut (38 mm) provided with the damper. This also tightens the damper into the strut.

The bellow I removed was very stiff. I had to cut it to remove the bottom cup that was installed in the new bellow (easy to do, the new bellow is much softer). By the way, used english tea boxes make nice bins to temporary store small parts that have been removed :




I inserted the new bellow into the damper and pulled its rod upward. Then the delicate part was to slowly jack down my DAF until the tip of the rod was more or less at the level of the bushing. I then installed back the bushing (I had no indication of the needed torque for the two bolts, but I think it is important to tight them up. I applied 4 m*kg). I decided to not install back the jack-and-crank holder, in order to check easily the top nut in the future. Moreover, the rod (that shall be used with the crank to move the jack and to remove the hubcap) is missing in my DAF and I have anyway an hydraulic jack and some tools in my boot in case of flat tyre  .  I put back the top cup and I tightened the new top nut (provided with the damper). It is a "Nylstop" nut and has no safety pin. I clamped the flat tip of the damper while tightening the nut until I could see the thread of the rod protruding (not sure if it is OK). I put back the wheel and the left side was done.

I thought the right side would be easier, but the castellated top nut was rusted and impossible to loosen, even after I soaked it in WD40 and waited for a day. I used a brutal method, drilling holes at the edge of the nut and then using a flat screwdriver as a wedge to separate the nut bits:

No other surprise on the right side, I proceeded as I did before on the left side (again with the painful and dirty oil pumping part ). To save time, I didn't remove the wheel that time. Having the wheel removed just makes a little easier the positioning of the (free) strut when removing or inserting the damper.

Job done ! So far, my DAF is more pleasant to drive now.