Dummie’s guide to carrier steering and brake adjustment please

[Big D]

Gidday all,

I’m wondering if I can get some advice on adjusting the brakes and steering on my Australian LP2A carrier. I’ve searched the forum and haven’t been able to find a definitive guide.

I haven’t had the carrier that long and since I’ve had it I had noticed that it required quite a bit of steering effort to get it to do hard turns. I’d also noticed that the brakes in general could not be relied upon and seemed really weak.

Moderate turns seemed okay but going around a ninety degree bend or turning on the spot required quite a bit of arm and shoulder work. Almost all of my use in that time had been on tarsealed surfaces for parades and displays, and I hadn’t had a chance to try it on a soft grass surface.

The problem became more apparent last weekend at a show where I ran the carrier on grass and very fine gravel driveway surface. What I found was that I couldn’t get it to do a hard turn to the left on the grass until I got onto the fine gravel surface, and the she started to come around.

Interestingly, thinking back to where I had driven it on the road, most of the turns were right turns so the problem has probably always been there but I just haven’t noticed it.

I had a couple of other club guys try it as well and they also noticed the struggle to get it to turn to the left. One of them also thought the right brake didn’t seem to be working that well.

Upon closer investigation, the bell crank on the left side seems well out of kilter. When the carrier is stationary, you need to rotate the wheel a good ¾ of a turn to get the left brake to come on.

The steering adjustment also seems a little off centre to, favouring the left side. That is, the steering column base seems canted to the left a little (from the driver’s seat) with the steering wheel in the central position.

I’ve read and reread the steering and brake sections of the manual now and I feel like I have a pretty good understanding of how the steering and braking system work. Now I need a bit of a Dummie’s guide to the best order to do it. I am also a little confused as to the points where some of the adjustments should actually be made.

From what I have gleaned from the manual, this is what I need to do, in this order.

1. Position brake operating lever so that the distance between lever axis and centre of brake pull rod clevis is 5/8”.
2. Adjust to ¼” the clearance between clevises at ends of brake rods and slotted steering control.
3. Offset bell cranks so that centre of outside clevis pin is 5/8” to the rear of bell crank pivot pin, or 9inch from face of rear bulkhead.
4. Adjust steering control links until brakes come on at just over half a turn on the steering wheel.

Have I got the general gist of this?

I have some questions at certain stages though:

• How much movement should there be in the brake operating lever when the brakes are activated? As it is, with the brakes fully applied, the brake operating lever moves by about 6mm. With the brake pull rod disconnected moving the brake operating lever gives a metallic sound, presumably as it comes into contact with the cam inside. I can’t get any other movement in it by hand though.

Should I be able to activate the brakes any further by hand with this lever? There seems to be no movement on it whatsoever by hand.

• The distance between the brake operating lever axis and the centre of the brake pull rod clevis is about 1” on each side of my carrier, rather than the 5/8” the manual says should be there. Is the adjustment for this as in point 1 above, done at the bell crank via the long pull rod that joins the two bell cranks, or is it just in the adjustment on the slotted steering control? From what I can see this long pull rod has opposing threads at each end.

• Is there a more scientific way of adjusting the steering control links rather than just by the approximate degree setting of the steering wheel indicated in the manual?

• If the steering adjustment is off centre, is it correct that I adjust this at the linkages running from the track displacement cam at the steering column base?


Hopefully I have explained things properly. Any advice would be appreciated.

Thanks.


Darryl

[Jordan Baker]

IM not sure how different the steering setup is in Aussie Carriers vs Cnd ones. On mine I had brake problems and it was due to worn out brake pads. The pads were about 1/8" thick. When I took the drums off I found that someone had brazzed on about 3/8" onto the brake pistons/actuators to give the pads more life.

I ended up installing NOS pads with all the parts set backout to the maximum as this just allowed me to get the drums on. This made a huge difference. After I did that I figured I should rebuild the linkages so I pulled out each component and rebuilt them one at a time. Now my Carrier turns as its supposed to.

I would recommend you check your pads and rebuilt them and then redo all the linkages and set them back to the specs in the manual. Those steps you listed were done for a reason.

[Jordan Baker]

ONe more thing. Check your track tension. If one or both tracks are loose then your steering is effected big time. Its way more noticable on grass then hard surfaces.

[Big D]

Gidday Jordan,

Thanks for the reply. I actually referred to one of your old posts in my searches. You were asking then about the length of the brake rods up near the bell cranks.

This carrier was restored from the bottom up by the previous owner. I'd be surprised if he put in worn brake pads but I guess one can't be sure without having a look. The track tension seems okay.

Can you answer the question about movement of the brake operating lever by hand?

Thanks

Darryl

[Jordan Baker]

The problem is that I know nothing about Aust. Carriers other then they share the same basic vehicle concept.

Not too sure what you mean by "brake operating lever by hand" and its movement.

Well if you think everything is in regards to the linkages then leave them. It could simply be track tension. On Cnd carriers a quick way to test tension is to clench your fist. Then where the track sags the most under the fender place your hand. if the gap is wider then your hand your track is too loose. If its a bit less then you track is fine. If its a lot less then your track is too tight. However that would then mean that your UC shoudl turn realy well.

Perhaps also your brake pads got some oil/grease leaking onto them. That would easily cause poor brakeing. Does it do this all the time even from a "cold" sitting. You can loose your brakes (steering) somewhat if your drums heat up and expand.

Still think the best way is for you to physically check out all of the specs and compare them to the manual. Take your hubs off and check the pads. if you have the tools or can borrow it should only take 1/2 a days work.

[Pedr]

G'day Darryl,

Have had similar experience with steering a carrier on loose surfaces. Especially turning right but not left easily.

The first and major repair that we undertook was to have the drums machined and the shoes rebonded with NOS pads. This has made an unbelievable amount of difference.

Another carrier that I worked on had all of the steering setup to the letter as described in the manual. I remember that one thing that we found that was critical was to start by setting up the steering column and steering wheel exactly as described. We started at first with the column one tooth out on the spline and it made a huge difference and had to start again. The spider on the bottom of the steering column must be parallel to the front edge of the drivers seat. and the spokes of the wheel need to be horizontal as they act as a sort of artificial horizon.

Another issue that can cause headaches with steering is track. It is important to have both sides equal in length. If one side is even marginally longer or tighter than the other, it will impact on your steering. In my experience the best way to overcome the length problem is to remove both tracks, lay them out side-by-side, and check the length. They should be identical. The manuals list the method to remedy this if they are not the same.

Track tension is another matter, but nearly as important to get even. My suggestion is to count the number of teeth interlocked on the track pawl. They should be even on both sides. This may take some amount of upper body strength and mind you don't hurt your back. ( It'll need some lifting )

You may also need to check your cam followers. With the steering column set in the correct position, your cam plate should be parallel to the steering spider, and the cam followers should be equidistant on the cross-shaft, with the bogies lined up with the remainder of the track wheels on the track, That is to say not biased to one side or the other. If your cross shaft is not even left to right, you might have tracking/steering problems built into the system.

I am of the opinion that all of this, is and will be an ongoing problem. I think that, as the brakes are required for both steering and stopping, and ofcourse we operate the steering more than braking, continous wear and heat will be a concern and must have been whilst they were in service(**). I have seen many carriers with grooved and or glazed drums and pads, and had difficulty in removing drums due to a deep groove on the edge of the drum. This I think is a weakness in the design of carriers and probably lead to the developement of differential steering in more modern variants like M113's. So, adjustments to steering and brakes will be a constant maintainence item similar to oil, water and battery.

Hope this is of some help, sorry that it's a thesis.

Pedr

( **, Has anyone ever asked a veteran carrier driver about what maintenance issues they had to attend to regularly involving steering and brakes? and if so could you post some comment here, Thanks )

[Big D]

Pedr and Jordan,

Thanks for the replies.

I had another look over the track tension that you both recommended as possibly contributing to the problem. It appears I was wrong and the left side track tension is less than the right side. Upon checking the track pawl I noticed that it was one notch out compared to the right side, just as you suggested Pedr. I am in the process of adjusting this.

The more I look at the problem, the more I think the issue is with the brakes. The brakes are like this all the time – they don’t deteriorate with use or heat.

I disconnected the brake operating levers yesterday and set up all the steering and brake rod linkage adjustments in the driver’s area. This all seems to be functioning properly now with the brake levers coming on at the right steering wheel angle.

What I might do is connect up one brake operating lever at a time and just test the operation of each brake individually. I do get the feeling though that I might have to go further into examining the brakes.

That was my reason for asking about the brake operating lever. I thought that the lack of movement in the brake operating lever was simply because the brakes were not being activated properly within the drum.

I’ll set up the track tension and test each of the brakes and then report back.
Thanks for your help to date.

Cheers

Darryl

[Big D]

Gidday all,

I seem to be making steady progress in getting my brakes and steering 100%.

I did quite a lot of mucking around with all the different connections trying to get it all set up as per the manual.

I also found that the steering box was seeping oil and there was little oil left in the box. I pulled the cover off and removed the shims and fitted a suitably sized paper gasket instead. That still hasn't done the job so will have to redo it again.

I have also adjusted one of the tracks and that is a lot better now.


One thing I haven’t yet been able to solve though and which is bugging me somewhat is this. When the steering wheel is at full lock to the left, upon releasing the wheel, there is a resounding clunk which judders through the steering system.

After disconnecting the steering rods and isolating the steering wheel from the steering cam, I have finally identified the culprit as the left side (viewed from the rear) clevis at the steering cam. There is a plate just forward of the cam which is bolted to the hull, and the clevis is actually dropping down below the height of this plate. When the steering is released, this clevis strikes the plate and then eventually rides over it with a clunk that causes a judder through the whole steering system.

It may not have been picked up when the carier was rebuilt. I can see some grinding down of this plate near the end of the hull crosss shaft, but there is nothing that I can see near this left side clevis.

I seem to be having major difficulty getting access to this point though and I wonder if there is any practical way to get to it short of a major stripdown. I have removed all the covers but it really only gives access to the right side clevis and right side of the cam.

I have taken some pictures of the offending clevis using my wife’s mirror placed under the driver’s seat. The steering is at full left lock and the left side clevis is as far back as it will go and you can just make out where it has dropped below this plate on the hull.

My question is, unless I am mising something, how can I best attack the problem? From what I can see, these clevises have a screw through the end that attaches them to the cam. Getting access to the one on the left side (as viewed from the rear) is a problem though. I can barely squeeze into the right rear crew area as it is (184cm and 103kg!).

If I could get this left side clevis off, I’m sure a little bit of grounding off of the edge would do the job, and allow the clevis to ‘ride over’ this plate on the hull a lot easier.

Does anyone have any bright ideas?

Any suggestions would be appreciated.

[Lynn Eades]

Is that your cam plate we are looking at. I will post a pic (that may have come from Ron, and it looks like Jordans been there) so that we can help I.D which bits your talking about.
If we are looking at your cam plate,and the long clevis, then it all looks too close to the floor. Is the cam plate assembled onto the mounting plate correctly? If you can get the two pins(screws) out, then you can pull the rods out, and then make them the same length. At this point you can drop out the mounting plate(with the cam plate on it) and though the hole, check the rollers etc.
My understanding is that once you have everything set up, all you have to do, is adjust the brakes at the backing plate.
I'll also post another bit, that should be credited to someone from the forum.
Thers a bit to getting these brakes together correctly. Different coloured springs etc.

[Big D]

Gidday Lynn,

Yes, the view I have shown in the photograph is (via the mirror) looking back along the floor of the hull, through the bulkhead in the drivers area, looking back at the clevis on the camplate. You can make out the camplate in one of the two pictures I posted.

In the picture you have posted, it is the left side clevis mounted on the camplate (labelled J) that is the problem.

The problem is that once this clevis is fully back (toward the rear of the carrier) it drops below a plate that is bolted to the hull around the area where the cross shaft goes.

As you say, it is simply a little too close to the floor. I would say it would only need 1-2 mm shaved off the underside of that clevis (or off that plate) but the problem is getting too it, so I could remove the clevis mounting screw.

Does that help explain my predicament?

Cheers

Darryl