XT Hand Brake Conversion To Disc Brake

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01 Nov 2012 12:01 #1 by dandjcr
dandjcr created the topic: XT Hand Brake Conversion To Disc Brake
Forum Home > OKA Maintenance > XT Hand Brake Conversion To Disc Brake

David Hallandal
Member
Posts: 133
I am looking in to a handbrake conversion from Drum to Disc on my XT, NP205 Transfer Box.
Question 1: How do you set up the Speedo Sensor, as there will no longer be tabs welded on the Drum for the pickup
Question 2: Anyone got part numbers for the Disc, Caliper, or required parts
Question 3: Anyone got some photos of a conversion
Any other advice?

Many thanks David
June 23, 2010 at 9:50 AM Flag Quote & Reply

Peter_n_Margaret
Member
Posts: 198
I saw one that Paul Nott did..............

Cheers,
Peter
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Cheers Peter, OKA196 Motorhome. www.oka4wd.com/xt196.htm



June 23, 2010 at 7:14 PM Flag Quote & Reply

joseph baz
Member
Posts: 331
Hi David,a while back I was talking to Paul Nott and he mentioned that the problem with the disc conversion was the inability to hold, that was the same problem that I had with mine, as per the sensors if you are to maintain the same circunference as per the drum sensors it should not be a problem, at the moment I am trying to sort out how my hand brake is going to work as I have a divorced mounted NP 205, once I get it to work how it should I will let you know.
Cheers
Joe
June 23, 2010 at 9:07 PM Flag Quote & Reply

Michael Hession
Member
Posts: 6
Just some thoughts to add to the discussion. Why change to a disc brake? From my understanding the main advantage with a disc brake is heat dissipation. Heat is not a problem for a hand/parking brake. A disc brake needs a higher clamping force than a drum brake to work effectively, a drum brake under load develops some clamping force of itself. To make the existing brake work better we need to make sure the existing system is working correctly and then maybe try to increase the force applied to the brake pad. From memory Collyn Rivers added a pulley system into the brake cable to increase the force applied when the brake handle is pulled on
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June 24, 2010 at 6:17 PM Flag Quote & Reply

Alister McBride
Member
Posts: 97
Hi Dave,
I was thinking about it myself for a while for various reasons. I haven't spoken to anybody with this setup to support my viewpoint but the main reason i haven't gone that way is that with normal disc brakes the pads remove any dirt/water initially through rotation of the disc when applied, however, with a park brake it is stationary when applied and therefore could be applying pressure to the pads while dirt/water are still between the disc and pad which probably wouldn't work very well...
Also, options, do you change to a hydraulic system which would mean changing the lever inside the cab? Or do you leave it cable operated and use an older cable operated disc brake setup (would you have enough pressure just by pulling etc...?)
The speedo issue is easy, just make a thin round disc which bolts between the driveshaft and brake disc which has four tabs coming off it, the speedo just needs four signals per revolution to give the right speed reading. Make sure the tabs are a similar proportion of the circumference they travel in, those sensors are relatively sensitive. The sensor could then be mounted on the brake calliper bracket...
Anyway, good luck whichever way you go!
June 24, 2010 at 9:47 PM Flag Quote & Reply

Aussie Bight Expeditions
Member
Posts: 109
Hi Dave,
I do not have the NP205 Transfer case but the Rockwell and the previous owner Frank Hawkey of Aussie Bight Expeditions put a disc brake on the original OKA that I still own and he did this as the sand stopped the drum working.. What he did was use the disc brake set up of the Nissan Skyline from the rear right hand side and then contacted it to the old hand brake lever from a BJ-45 land cruiser. Used the brake cable from the L/C hand brake and the cable from the Skyline joined them together and it works well. The hand brake unit is by the fire wall below the drivers seat and sits against my left leg, no problem and he told me that is how the clamping force was obtained.
I realise they are different boxes and I do not have an issue with the speedo, but we are stopping the same weight when stationary and it will hold on a 50 degree slope that I some times park on. So I know it holds.
I have not done this to my No 2 OKA as I have modified the original Rockwell assembly and wash it out every day that I use it near a beach.
Hope this is of some help to you as well.
June 25, 2010 at 7:06 AM Flag Quote & Reply

Aussie Bight Expeditions
Member
Posts: 109
Just a thought not all disc brakes use the hydraulic system, that is why the Nissan Skyline was used as it a manual lever system and it does a good job. With the dirt etc in it I have not found that to being a problem but then this bus does mainly beach and true sand work not mud work, once again good luck on your hunting of ideas. Will not be home till last week of July can photo and show you how it was done if you need any further ideas.
Regards Tony
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June 25, 2010 at 8:47 AM Flag Quote & Reply

OKA4WD.com
Administrator
Posts: 412
From Allan Marshall:

David, I have a disc and caliper to make a hand brake setup for the ROCKWELL transfer case which you can purchase at cost.
The disc bolts on to the existing flange (where the drum fits to) and has a spigot facing towards the rear to mount a carrier bearing.
You would need to manufacture a mounting for the carrier bearing.
I made one which is basically a frame using channel iron fitted to the main mounting bolts (4).
Just took the 24mm nuts off and sat the frame over the studs and fitted the nuts back on. (I can supply a design of the frame and fax if necessary as it needs a bolted joint somewhere to split and fit and to align the bearing).
I have also seen a carrier frame which was fitted to the retaining bolts of the internal shaft end plates but looked a bit complicated to manufacture.
I had the disc made up to fit to one of my LTs but ended up using the carrier bearing on the existing drum setup and it worked well.
You would also need to mount the caliper and modify the cable action in the right direction.
A bit complicated.
By the way, the Rockwell hand brake drums are worth checking for balance as some of them are miles out.
They can be balanced on most wheel balancers by using the stick on lead weights but then it is best to weld a similar weight of steel onto the drum as the lead will throw off even if it is tech screwed on.
I had one which was 40gms out on one side and it made a huge difference to the vibration underneath. Those drums travel at an amazing speed (I don't think they were ever designed for this application).
Regards, Allan Marshall, Lake Grace, Western OZ
June 30, 2010 at 12:20 AM Flag Quote & Reply

OKA4WD.com
Administrator
Posts: 412
From Rod Lyons:

G,day David, I tried a disc park brake when I had the Allison auto in my truck & it wasnt that successful. I now have a Nissan Patrol transfer case with the Nissan park brake (drum type) with the Patrol park brake lever & this works great. It is no bigger that the OKA drum but it works well. The lever takes up a bit of knee room but I will put up with this for a good park brake.
You may be able to improve the OKA park brake with a lever. Leverage would be much better than the dead feeling of the pull type!
Rod
June 30, 2010 at 12:22 AM Flag Quote & Reply

OKA4WD.com
Administrator
Posts: 412
From Peter_n_Margaret:

Dave,
Why not try a simple extension to the actuating lever at the drum? There seems to be plenty of room to do this.
You could probably do a quick job on this to trial it without spending any $$$s, and it should give some extra leverage without too much hassle.
Lets know if it works, because I have been thinking of doing this for a while but have not got around to it yet...
Cheers,
Peter
June 30, 2010 at 12:23 AM Flag Quote & Reply

Tony Lee
Member
Posts: 539
Biggest problem with the OKA hand brake is the straight pull with your left hand. Just at the point where you need to get maximum force, the handle is right out, your arm bent at the elbow and your upper arm and back hard up against the seat so no way to get more leverage. Only vehicle I've owned that came close to being as poorly designed was a 73 Range Rover. To get it through rego, I had to pull up around the block, adjust it up so it was dragging and then once tested, get underneath again and slacken it off again.
--
Tony

picasaweb.google.com/114611728110254134379

June 30, 2010 at 5:22 AM Flag Quote & Reply

dingo
Member
Posts: 14
Some one pulled in last year on their way up to Cape york, can't remember who. They found that a model of international truck had the next size up drive train handbarke. 6" rather than the OKA 4" if my memory serves correctly. It was a very simple conversion which made a big difference. The brake should be available from every truck wrecker accross the country.
I extended the brake linkage arm, stripped the old falcon hoples hand actuactor regreased it with a light grease. The brake is now OK enough to take off my do now list!
Tim.
June 30, 2010 at 7:18 AM Flag Quote & Reply

David Hallandal
Member
Posts: 133
Hi Guys, Many thanks for all your input, the main reason I was looking at the Disc Brake option, came about after returning from a reicent trip to find the drum brake full of gravel and mud.
I am fortunate than my handbrake works well I was just looking at other options,
I also have a XT here with a LT Rockwall Transfer Box in it and looking at converting it back to a NP205 but needed to look at handbrake options for it
Has any one looked at using the Speedo sensor moving it to the speedo mount hole on the back of the NP205 this would make the 205 the same as the rockwall sensor
June 30, 2010 at 8:08 AM Flag Quote & Reply

Brendan Eblen
Member
Posts: 14
Hi fellow OKA owners, hope this is useful.
My hand brake function was greatly improved with the shoes being bonded with a suitable material, Power Brakes in Adelaide rebonded my OKA handbrake shoes with material used on fork lifts. The result was very impressive, no other modification was required for a fully functional handbrake.
Regards
Brendan Eblen
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July 2, 2010 at 6:24 PM Flag Quote & Reply

Outback Jack
Member
Posts: 381
Would a NT hand brake work? I know it is different transfer etc.
August 8, 2010 at 9:16 PM Flag Quote & Reply

Paul & Sue Crompton
Member
Posts: 44
I can confirm what MIchael said about Collyn Rivers adding a pulley system to increase the force on the drum. It works fine as a handbrake on hills however a while ago I had a complete brake failure and I used the handbrake as an emergency brake. I pulled it as hard as possible and it made no difference whatsoever. Just as well I was in first gear but as I said it works fine on hills as a park brake. If you were to do a simple extension as Peter suggested and also a pulley system, I am sure this would be an economical way of making the handbrake work better provided you have enough travel with the handbrake coming out of the dashboard (still don't like under dashboard pull handbrakes).
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Paul & Sue Crompton

August 9, 2010 at 7:44 PM

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