DO35 Hitchmaster.... a hint which may avoid catastrophe

Submitted: Tuesday, Jun 03, 2014 at 13:25
ThreadID: 108088 Views:25038 Replies:8 FollowUps:17
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This may be common knowledge, or it may have been covered before but I thought I'd share with you an experience that happened to us two weeks ago. 10 k's south of Mount Isa, the DO35 coupling came apart! The Tvan  stayed behind us on the safety chains, but as I discovered when we stopped a couple hundred metres later, it wasn't staying on for much longer. What happened I've covered here as two subjects.

1) The M5 x 40 stainless steel wave pin that holds the castle nut on the rear of the coupling in place had rusted away and broken off. The only part left of it was the bit that goes through the shaft. I had to use a hammer and punch to remove it. But sufficient of it had disappeared to allow the castle nut to wind itself off. I had noticed a dull kinda thud now and then for a couple of days beforehand, and I had looked around the tow bar but assumed it was the Haymen Reece assembly "natural movement". When the castle nut finally wound all the way off, the shaft slid forwards out of the hitch block and set the Tvan free! Luckily the chains were on..... but were they fitted correctly?

2) When we picked up our Tvan back in 09, the bloke doing the hand over set our chain length and we haven't altered it. I assumed wrongly that he had set it correctly, but in fact he hadn't as we found out when the events described above occurred. With the Tvan free of the DO35, and even though the chains were crossed, the drawer bar lent downwards and the safety chains dragged on the bitumen, grinding down the forward two nuts and bolts and also grinding away at the safety chain. One of the links ground far enough through that it disconnected from the drawer bar and was swinging in the breeze, the other was about 2 mm from following suit. In a bizarre occurrence, the castle nut must have caught on the drawer bar till we stopped because we found it right beside the trailer in the dust of the roadside. So with the aid of our Hi-lift jack to get the Tvan back on its jockey wheel, we successfully put it together to get us into Mt. Isa where we stayed till Monday morning when I could buy supplies to fix it properly. We cleaned the assembly with degreaser, re-greased it and put it together and put a large split pin to hold it till I can source the correct pin when we return home. I check that pin every day! I have shortened the chains as well, trying to keep them of a length that won't allow the trailer drawer bar to drag along the ground should this occur again.
So that's the story.... I thought 'd post the story here in case someone doesn't know it can happen. This could have been a very ugly accident, luckily for us it had a happy ending and we've been having a great holiday with our Tvan.

Sad that I find this bit necessary but let me make it perfectly clear that I do NOT believe it is a faulty product, Track Trailers are NOT irresponsible for this event, and the makers of the Hitchmaster DO35 are NOT responsible either. It was a wear and tear thing. Plain and simple.

Also, the Hand Over Guy is NOT responsible for the chain length thing.... I am!!

Cheers

Brian
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Reply By: Slow one - Tuesday, Jun 03, 2014 at 13:38

Tuesday, Jun 03, 2014 at 13:38
Brian,
thanks for posting what happened to your gear, any info like this helps and some will go and check their hitch.

Fella that I regularly meet when out walking had a tow ball break recently writing off his van and vehicle, at least he and his wife were ok. It was his first trip with a van and he had a HR tow bar fitted to his Pajero. He said to the fitter should he replace the old ball, the answer was know it will be fine. In hindsight it would have been a very cheap $15 investment.

Nice to see no one was hurt in your accident.

AnswerID: 533659

Reply By: disco driver - Tuesday, Jun 03, 2014 at 15:00

Tuesday, Jun 03, 2014 at 15:00
One of the problems with some of the towbars available today is that the shackle holes are so far in front of the actual ball/treg or whatever, that the chains have to be excessively long to reach, even when crossed.
Should anything go wrong (hitch/ball failure) the drawbar will sit in the crossed chains as intended but will still hit the ground because the chains are too long

As an aside to Brian, the castellated nut should have had a lock washer between the nut and the tongue to prevent what happened with the nut unscrewing.

Glad that no one was injured but it could so easily been worse.

Disco.
AnswerID: 533661

Follow Up By: Brian C 5150 - Tuesday, Jun 03, 2014 at 15:50

Tuesday, Jun 03, 2014 at 15:50
Thanks Disco, but no lock washer used here because it would inhibit the lateral movement of the DO35. The wave pin is the "lock washer." If the castle nut is too tight, the shaft cannot move in a sideways motion.

Cheers

Brian

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Reply By: Ross M - Tuesday, Jun 03, 2014 at 18:29

Tuesday, Jun 03, 2014 at 18:29
Brian C 5150
I presume the wave pin is a Roll pin ie, hollow tempered steel/spring in a cylinder format.
I haven't seen one which is stainless used in that situation.
Can't see how a stainless one would have rusted away, perhaps a steel one can though.

What has it been washed in to cause it to rust?
If lubricated and /or greased there should be some residual greasy film to inhibit corrosion.

A big dob of silastic or urethane sealant will also assist in holding a nut in place to persuade it to stay there even if the pin did disappear.

The thud would have been the longitudinal sliding of the shaft in the bushes when the nut hit the bushing enclosure under acceleration or the bushes hitting the hitch when braking.
A noticeable gap must have been there but it isn't something you go looking for.
For it to slide out there must have been considerable slack in the chains to allow to the retreat sufficiently for the drop off to occur.

I have an '05 Tvan and it has a roll pin it that nut but earlier type unit. There is no corrosion whatsoever around or near the pin.
Is it possible someone has tried to unscrew the nut and sheared off the pin or tampered with it in some way?
AnswerID: 533672

Follow Up By: Brian C 5150 - Wednesday, Jun 04, 2014 at 08:02

Wednesday, Jun 04, 2014 at 08:02
It is a wave pin, according to the manufacturer it is a M5 x 40 wave pin. Similar to a rolled pin but slightly different. According to the manufacturer it is stainless steel. I rang them before repairing the unit. I have replaced it for the rest of our trip with a split pin till I can source a replacement and spares etc....

In 2010, with our Tvan only 6 months old, we did a 7 week trip through the red center, while there was lots of water and mud. On our return, we had rust issues with the jockey wheel, the stone guard and the 4WD. Track replaced the jockey wheel and the stone guard very graciously under warranty. The 4WD had been replaced last year after the rust became to much. We had previously camped on Fraser Island (9 times and Nth. Stradbroke Island (2 times) with no rust issues, but the salt and minerals of a wet desert was a different story.

The "thud" was indeed the longitudinal movement, but not something I was looking for, hence I missed it. I explained the issue of the chains.

It IS possible someone tried to remove the nut, but the pin looks corroded on both the edges from the piece that I removed from the shaft. As opposed to forcibly broken clean edges.

My post here isn't to whinge, or lay blame, just to let others know of something that "might" occur and therefore be aware.
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FollowupID: 817101

Follow Up By: Shaker - Wednesday, Jun 04, 2014 at 09:40

Wednesday, Jun 04, 2014 at 09:40
I can assure you that the pins that split in my coupling were zinc plated & not stainless steel.



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Follow Up By: Shaker - Wednesday, Jun 04, 2014 at 09:42

Wednesday, Jun 04, 2014 at 09:42
I just Googled "wave pin", mine were basic roll pins.
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Follow Up By: Ross M - Wednesday, Jun 04, 2014 at 10:13

Wednesday, Jun 04, 2014 at 10:13
Thanks Brian.
I cannot see how a stainless item can erode/corrode or disappear like you describe.
There are many vehicles which live in the outback and don't experience the salt and minerals of a wet desert as you described.
If they did, the vehicles which aren't stainless would all be rusty. Just isn't like that.

I would think the pins cannot be stainless. If that situation was true then split pins might only last a couple of weeks based on the antirust properties of stainless V mild steel.

I like makers who rename items from say, Roll pin, to Wave pin. Possibly it is an alternative supplier who can't use the term Roll, so the company adopts that in their blurb.

Sounds mysterious and marketing related to me.
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Follow Up By: Gone Bush (WA) - Wednesday, Jun 04, 2014 at 13:40

Wednesday, Jun 04, 2014 at 13:40
A roll pin and a wave pin are too different things.




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Follow Up By: disco driver - Wednesday, Jun 04, 2014 at 15:14

Wednesday, Jun 04, 2014 at 15:14
Can anyone explain the advantages of a "wave" pin over the normal roll pin.
As far as I can see they both are forced/pushed through a hole to locate two things in position, held there by friction caused by the pin wanting to expand because it is compressed when forced/driven in, and both should do the same job equally effectively.

or is it just Marketing blurb, as I suspect.

Disco.
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Follow Up By: Gone Bush (WA) - Wednesday, Jun 04, 2014 at 15:24

Wednesday, Jun 04, 2014 at 15:24
I've only looked into these things just recently, but it seems that Wave pins are stainless steel and Roll pins are mild steel, therefore subject to rusting.

I don't know if that's a hard and fast rule though.

Trying to find a retailer that sells in small quantities is proving to be difficult.



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Reply By: Motherhen - Tuesday, Jun 03, 2014 at 19:00

Tuesday, Jun 03, 2014 at 19:00
With our set up, the chains also made a skid pad under the a-frame when our tow hitch broke towing our Bushtracker caravan. If the chains were shorter, they would not allow full movement and would be under stress, shortening their life. The chains were a little worn, but in the short distance until pulling the rig onto the edge of the road, they did their job well. They were of course replaced after that.

Motherhen
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AnswerID: 533676

Follow Up By: Shaker - Tuesday, Jun 03, 2014 at 19:40

Tuesday, Jun 03, 2014 at 19:40
I believe that in WA you can be fined if your chains aren't crossed & if the coupling can touch the road surface in the event of a failure.

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Follow Up By: Motherhen - Tuesday, Jun 03, 2014 at 20:36

Tuesday, Jun 03, 2014 at 20:36
Hi Shaker

While it makes sense to have them crossed to allow for more movement (turning circle), the Western Australian Drive Safe booklet states

"Your trailer or caravan must have:
- the correct coupling;
- at least one safety chain for vehicles up to 2.5 tonnes aggregate trailer mass (ATM) and two safety chains for vehicles between 2.5 and 4.5 tonnes ATM. The chains must be cross-hitched so that the trailer or caravan will still be secure if the coupling breaks;"

Some years ago, Drive Safe booklet used to state that they must hold the a-frame (or what ever terminology they used) from touching the ground. That wording was changed, no doubt after finding it was impossible to safely achieve with many trailers.

Even if you only have one chain with a lighter trailer, it should still be hitched diagonally for movement. To go for two chains would be even better if your trailer was to set up a dance on the single chain.

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Reply By: Shaker - Tuesday, Jun 03, 2014 at 19:01

Tuesday, Jun 03, 2014 at 19:01
I had a similar issue with a DO25 hitch, both roll pins split lengthways, rang Vehicle Components, not only didn't they care, but didn't know the dimensions to send me new ones. I ended up using stainless steel ones.
Personally, I think there should be a recall before somebody is hurt!

AnswerID: 533677

Follow Up By: Brian C 5150 - Wednesday, Jun 04, 2014 at 08:06

Wednesday, Jun 04, 2014 at 08:06
I rang Vehicle Components and the guy in the service department couldn't have been more helpful. In my case, which is all I can comment on, it isn't, in my opinion, a recall issue. It's simple wear and tear.
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Follow Up By: Shaker - Wednesday, Jun 04, 2014 at 09:53

Wednesday, Jun 04, 2014 at 09:53
How can it be wear & tear, how many people would be expected to get a hammer & a pin punch, drive out the roll pins & check them??
Roll pins are not a wear & tear item any more than a flywheel key would be!


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FollowupID: 817111

Reply By: Member - Andrew & Jen - Tuesday, Jun 03, 2014 at 21:13

Tuesday, Jun 03, 2014 at 21:13
Hullo Brian

Thanks for sharing your experience

I have just gone out and had a gander at both my Hitchmasters - the 25 on the Tvan and the 35 on the BT. Both are 9+ years old and thankfully in good condition - tensioned and with no corrosion around the pins. Since I have owned them, I occasionally give them a puff of CRC.

I wonder if the Tvan has been towed on beaches/salt water or some other corrosive environment.

I am curious you have a 35 on the Tvan as it only weighs ~1.3t. Unless you put it on for ease of coupling up.

Did you use the trailer brakes immediately you realised what had happened and for gently slowing up, as this keeps the chains tight and reduces the tendency of the A-frame/chains scraping along the abrasive road surface.

As far as service from the manufacturer is concerned, my experience has been very positive, with the comment "This should not have happened" and (small) parts sent with no charge.
Cheers
Andrew
AnswerID: 533687

Follow Up By: Brian C 5150 - Wednesday, Jun 04, 2014 at 08:16

Wednesday, Jun 04, 2014 at 08:16
The Tvan is an '09, it came with the DO35 fitted. It has been on Fraser Island and Nth Stradbroke Island, as well as the Red Center and Simpson Desert in very wet salt/mineral conditions. I have always washed it and cleaned it, but clearly the rust gets in!!

I found the trailer plug disengaged when we stopped, so have no idea at what stage the trailer brakes worked till or what part they played in all of this.

Yep, I'm very happy with the response I had from the manufacturer.
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FollowupID: 817104

Follow Up By: Shaker - Wednesday, Jun 04, 2014 at 09:54

Wednesday, Jun 04, 2014 at 09:54
The DO25 was discontinued years ago.

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Follow Up By: Shaker - Wednesday, Jun 04, 2014 at 09:57

Wednesday, Jun 04, 2014 at 09:57
Damn, no edit function!

Forgot to add, I also have both, DO25 on the Tvan & DO35 on the AORC Quantum, I think the DO25 is a better engineered hitch & nicer to use than the DO35.
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FollowupID: 817113

Follow Up By: Member - Andrew & Jen - Wednesday, Jun 04, 2014 at 11:01

Wednesday, Jun 04, 2014 at 11:01
Brian, hopefully it won't happen again with preventative maintenance.

The length of the connecting wiring on the Tvan is not sufficient to cope with the increased distance if the hitch parts company. I may knock up a small extension, to be removed offroad.

On the BT, I made sure there was enough slack to cope, as the consequences of hitch failure is potentially much more serious.

Cheers
Andrew
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FollowupID: 817116

Reply By: Nev (TAS) - Tuesday, Jun 03, 2014 at 21:21

Tuesday, Jun 03, 2014 at 21:21
Hi Brian,
just a point with the chain length. I am sure you have it covered but make sure you can turn the Tvan without the chains limiting it. I adjusted my van and first time I backed in at an angle the chain almost stretched.
Travel safe
Nev
AnswerID: 533688

Follow Up By: Brian C 5150 - Wednesday, Jun 04, 2014 at 08:14

Wednesday, Jun 04, 2014 at 08:14
Thanks Nev..... good advice.
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FollowupID: 817103

Reply By: Gone Bush (WA) - Wednesday, Jun 04, 2014 at 08:15

Wednesday, Jun 04, 2014 at 08:15
For everyone's info:

Wave Pin M5X40
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AnswerID: 533697

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