Hand Brake Cable. Need for maintenance check.

Submitted: Monday, Aug 16, 2004 at 22:07
ThreadID: 121391 Views:3742 Replies:5 FollowUps:0
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In October last year I had our hand brake cable break where it went through one of the links welded to the chassis that BTi use as guides for the cable. I replaced it with a new one, and in an attempt to improve the way the cable was run instead of using the chain links that BTi weld to chassis to run them through, we fitted poly blocks with a hole drilled through them to give the cable a bigger area to pull on instead of just the narrow link area. This method of running the cable has proved to be no better than what BTi use, as the 4mm cable has worn our where it went through one of the poly blocks as well as causing wear on the poly blocks. An additional problem with the poly blocks was that rocks have also smashed some of them. When I removed the cable I also found that where the cable bends around the brake control lever it was worn through half of the cable. Since fitting the new cable in October 2003, the van has travelled about 20,000 km with a lot being on corrugated roads. I think Steve Gibbs is right again when he says corrugated roads cause a lot of problems and strange things to happen with vehicles and caravans. I believe that the wear on my cables is probably due to the constant virbations on the corrugated roads. I would recommend that everyone regularly check the hand brake cables for any signs of wear, especially where it runs through the links and at the connection point to the lever at the back of the brake drum. Next time I see Steve I will try to remember to suggest to him that it is included in their guide to maintaining the van. Brian
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Reply By: Deleted User - Tuesday, Aug 17, 2004 at 13:27

Tuesday, Aug 17, 2004 at 13:27
Brian have you thought about running the cable through turning blocks as in the cheaper marine cable and drum steering systems, it would at least stop the point contact and sliding everytime you apply the handbrake. Greg
AnswerID: 564795

Reply By: Deleted User - Tuesday, Aug 17, 2004 at 21:08

Tuesday, Aug 17, 2004 at 21:08
G'day Greg, et al, The marine cables that are in steering systems are not in a very high loading situation compared to how our cables are run in the BT's. I'm not sure the pulley blocks would take the load in the wheel mount area ..whether a bush or bearing. One particular cable angle change near the brake arm is highish load. Couple this with dust and stones and the failure rate might be higher than the original set-up. I have been looking at a solution for mine as mine are worn (D rings on chassis) even without going on severe corrugations. A real solution involving some engineering and a professional cable maker is the way to go ...albeit an expensive exercise in the short term. I have spoken to a manufacturer of truck cables (handbrake, pto, cable latches etc) and he has assured me he can make a cable well suited to the job. The cable will be like a 4x4's handbrake cable i.e. an inner cable of 5mm diameter ...and inner sheath of wound steel ...an outer sheath of tough plastic ...greased for life and sealed from dust at either end. The cable can be any length with swagged ends, at each end. The OD is around 1/2 inch and this cable is suited to a Mack truck and has a service life around the same as a 4x4 handbrake cable in the outback which is quite a long time. The mount at the wheel end is via a 6mm steel plate with a slot and drilled hole to take the cable outer ..the swagged end is held captive in the brake actuating arm via a matching fitting supplied with the cable. The cable then runs all the way to the front of BT about 2 feet short of the handbrake lever where another plate is mounted with a slot on drilled hole to take the cable outer. The cable is attached to the handbrake lever via a fitting that about 4 ft of original cable with the adjustment left intact .. or a single arm can be made that the new cable fittings attach to ..the arm is threaded at one end to facilitate adjustment. Cost of the cables ...I was quoted around $220 per cable plus fittings .... and of course fabricating and fitting of the whole thing. I was only after the cables because I would fabricate everything else in my case ... making it around $500 for me for the system. Drive in drive out for someone else would be prohibitive in cost. There are other ways around the problem .... the cable eyes (and/or cable) wears because the materials are dissimilar and the load is concentrated at a small surface area .... small eyelet (4-5mm) giving small radius for the cable to run over coupled with a small diameter cable ... another small radius concentrating load. Spread the load over a greater area and supply some lubrication and the wear rate drops markedly. To illustrate the point imagine the cable running through a piece of pipe 6 inches long and bent to the same arc as the cable angle change ...all of a sudden the load is taken up by 6 inches of wear surface instead of the small surface area of cable eyes now. Add a bit of dry lube and wear is much lower. This could be done now ... grab a 4 inch piece of thick wall tube that fits through eyelet and bend to match cable arc at that point. Undo cable and slide tube on cable all the way up to and through eyelet. You could tack the tube onto the eyelet .... maybe ? Ideally a collar either side of the eyelet holding the pipe captive would be better at pipe change time (not very often). There is two ways to go really .... spread the load over a greater area so it takes forever to wear or have a sacrificial piece at the wear area that you replace on a periodic basis that doesnt involve welding on the chassis every time. Food for thought !!! Get to it ...........[wink] Regards Anthony Explore this Great Land ...Do it Easy ...Tow a Bushtracker
AnswerID: 564796

Reply By: gottabjoaken - Tuesday, Aug 17, 2004 at 22:10

Tuesday, Aug 17, 2004 at 22:10
Please excuse my ignorance here, Brian and Anthony, but why do the hand brake cables wear through anyway? Surely they are not under tension-release-tension-release, so it seems to me that the reason must be that the slack cable is just flopping about against the guide and therefore wearing with the abrasive qualities of our great brown land. So, wouldn't some way of applying tension in the cable - without applying the brakes of course - be a solution? I must admit, the sealed outer sheath seems like the best solution, just like any ordinary vehicle brake cable. Not too expensive a solution at construction time, since it appears to be a common problem. Ken and Joan
AnswerID: 564797

Reply By: Luvntravln - Tuesday, Aug 17, 2004 at 22:22

Tuesday, Aug 17, 2004 at 22:22
Hi This definitely should be on the Copeton discussion list! tgintl/jay
AnswerID: 564798

Reply By: Deleted User - Tuesday, Aug 17, 2004 at 22:52

Tuesday, Aug 17, 2004 at 22:52
G'day Ken, I thought it was a brake off, slack cable problem whilst on the move that was causing the wear. On closer inspection the cable is only cutting through the eyelet in one spot ..and that spot is where it sits with the handbrake applied. I would assume if it was a slack cable whilst travelling wear pattern .... the eyelet would show a wear pattern around most or all of its inner surface (not concentrated in one spot) the cable would show a wear pattern at one spot but around its whole circumference ??? My cable seems ok it just the eyelet being cut through like its being done ever so slowly with a small round file in one spot. I put this down to the cable being very rough and hardened from the galvanising process (harder than the mild steel eyelet and the softer has to give ) and the tension on, tension off, giving the saw action ? In Brians case it could be a different wear pattern from a different cause ... (slack cable and corrugations or just corrugations) ??? To put it in perspective ...my eyelets are not anywhere near worn through but a groove is being cut into it. Just sumthin' to keep an eye on over the next couple of years. I have a replacement cable to go on ... smoother finish and larger diameter. The cable is still sitting in the shed of course !! [wink] Its on the list of "to do" ... My BT is also nearly 3 yrs old ..I dont think BTi use this exact cable to-day ?? I remember noting that later BT's have a larger diameter smoother cable and its probably not the problem it once might have been ?? Regards Anthony Explore this Great Land ...Do it Easy ...Tow a Bushtracker
AnswerID: 564799

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