Massive 109 six cylinder brakes on my 88

[Bandog]

Just replaced the front brakes on the hybrid, they are like truck brakes. I am wondering if this vehicle will really need a disc conversation with such large drums and shoes. My friends tdi series has the original 88 hubs and drum brakes on his 2a and just gets away with it. I have had them fade on me once, when braking really hard from speed.

[lo-fi]

My 109 with the six cylinder setup and servo also stops on a dime, so my thoughts of disk conversion also disappeared a long time ago! Still a slight pain when they get wet, of course, but I guess it's part of the charm

[FridgeFreezer]

The 6cyl setup isn't bad if it's in good nick, how did you manage to overheat them?

[Soren Frimodt]

1 hour ago, lo-fi said:

My 109 with the six cylinder setup and servo also stops on a dime, so my thoughts of disk conversion also disappeared a long time ago! Still a slight pain when they get wet, of course, but I guess it's part of the charm

I have had the exact same experience, absolutely no performance problems with drums if they are in good nick, however I've never regret going to disks! First off the performance after going through a puddle, or in mud is not nearly as effected as with drums, it can become downright dangerous with drums, I nearly ran a guy over once after going through mud at speed to gain momentum up a climb, I didn't make it to the top, and came back down almost as quickly as I went up, sadly this bloke figured I would get up it so stepped onto the track behind me... Luckily noone was hurt. Also the perfomance on road is actually better, simply because it is so much more predictable, a given amount of pressure on the pedal always gives the same amount of braking.

Edited February 10, 2017 by Soren Frimodt

[Bandog]

1 hour ago, FridgeFreezer said:

The 6cyl setup isn't bad if it's in good nick, how did you manage to overheat them?

Nearly missed a junction touching a tonne :-) his are the little ones though, on the little hubs. Standard 88 2a. These 6pot drum brakes look like more at home on a 3.5 tonner. It's got the mofo servo too. As pictured. When I bought this vehicle, it had an old single line master. It's the first thing I changed!!! 

Edited February 10, 2017 by Bandog

[daslandroverman]

The 3 inch wide shoes on the V8 and Forward Control models are even better. 

A decent master/servo and they stop really well.

My mates IIA FC with a Cummins 6b engine also got the air assist master cylinder from the truck the engine came from. Stand on the pedal with a little vigour and you can stall the engine at 15mph in 2nd gear.

[garrycol]

On the FC 101 the standard drum brakes are as good as the same vehicle fitted with disks - however with disks the vehicle always pulls up straight where with the drums hard braking can get exciting trying to work out where the vehicle is going to go.  For sure not such an issue with new drums and shoes and correctly adjusted but how often is that situation met where the disks just keep on breaking straight and level time after time.

 

Brake testing on a 101 (same brakes as a Stage 1) - shows how well drum brakes can work on a 2.1t unloaded vehicle.

 

 

Garry

Edited February 11, 2017 by garrycol

[Bandog]

The unpredictable braking is suppressed slightly by the power steering box. 

Also if you hit a bump or soft mud the steering wheel is less likely to be ripped from my hands, as was the case with the original steering 

[Bandog]

8 hours ago, garrycol said:

On the FC 101 the standard drum brakes are as good as the same vehicle fitted with disks - however with disks the vehicle always pulls up straight where with the drums hard braking can get exciting trying to work out where the vehicle is going to go.  For sure not such an issue with new drums and shoes and correctly adjusted but how often is that situation met where the disks just keep on breaking straight and level time after time.

 

Brake testing on a 101 (same brakes as a Stage 1) - shows how well drum brakes can work on a 2.1t unloaded vehicle.

 

 

Quite impressive really. 

[Snagger]

Disc brakes won't give stronger braking - you're already limited by tyre grip with the standard 10" drums, let alone uprated 11x3" drum brakes.  The servo makes the legwork a big deal easier, but fitting massive brakes to a smallish vehicle makes stopping harder, not easier, because you're more likely to skid.

Disc brakes make servicing easier and maybe shed heat a little faster, though I doubt there is an enormous difference in that.  I think they're easier to control under heavy braking, getting closer to maximum without locking, but that might just be me or an idiosyncracy in the systems I fitted, but bigger brakes and discs won't shorten your braking distance.

[Bandog]

Nick my dear man, it's not so black and white. I have six cylinder brakes because I have substituted weight for speed. 

Plus, the other modifications also make the vehicle much heavier than standard. The brakes will help me when towing for instance, a must with the 200 tdi swap and I have wider than standard tyres 

Edited February 13, 2017 by Bandog

[Snagger]

The brakes will still have more grip on the drums than the tyres on the road.  You can only change that by adding load to the vehicle, not by towing.  You need down force on the tyres to increase their grip to increase the braking capability.  By increasing drum and shoe area and hydraulic pressure via a servo, you are just increasing the car's propensity to skid.

[WesBrooks]

My experience of drums all around is a while back now on a '74 VW1303. When cold they tended to snatch and after lost their bite quite quickly when running around 60mph country lanes.

Despite working in engineering I never really appreciate things like why people want discs over drums or bigger discs until I get a bit of hands on myself. For me the this has come in two chunks.

Firstly going back from hydraulic discs on my mountain bike (set up as a commuter at the time) to rim brakes on a push bike really made me appreciate the confidence discs gave in being able to measure in braking gave which allowed me to make better use of my back brake and hold the front at as close to perfect braking as I could muster. This ultimately shortened my braking distances  because as the error is (ie with drums you had less of an idea how much braking you were going to get with a certain squeeze) less you are more likely to squeeze the brakes harder from the instant you perceive a need to loose momentum. While ultimate braking is dictated by the tyre grip if you can get to that ultimate quicker the drum system will never be able to out brake the discs in order to catch up for the little 'lets see how it feels' initial press. Yes the road bike didn't have drum brakes, but the issues were similar to what people have already said regarding consistency.

The second awakening came when I followed a brake in procedure for my wife's Toyota Yaris. A small car and equipped with discs up front and drums to the rear. The break in procedure had a number of breaks from 45 right down to about 10 and the difference between the amount you had to press the pedal down and how quickly the car stopped on a given foot pressure was quite scary on repeat runs. I really had to brace myself between the seat and peddle to get close to the ABS judder on repeat runs. After a bit of a short drive they had recovered most of the initial bite and where back to normal. So in a race, fast twisty road, or heavily loaded I could really appreciate why people wanted better breaks, to reduce peak temperatures (same energy being dissipated through a larger volume) be able to shed heat faster and in some cases pad choice to be able to tolerate the higher temps better.

From a mechanical standpoint I just prefer the pad force being applied to the disc from either side. The pads can't move far as they are directly compressing a lump of steel applying compressive forces to the material. With a drum you are creating a hoop stress in the drum and expanding the material. Doesn't seem too greater thing to do to a cast item. This is a similar logic to favouring braided hoses in the brake lines to reduce pedal travel and working being done on expanding things rather than braking.

All that said though if you keep on top of your maintenance and have good quality shocks, tyres, and the brake system is in good fettle then your in a better place than many of the heaps of tat you see on the road that only get tweaked each year as required to achieve an MOT. The usual advice on driving technique, leaving gaps and not dabbing the brakes all the time will probably be far more effective in improving the chances of you avoiding a nasty than the people who are forever dabbing brakes or trying to rub up against the bumper in front.

Edit: I owned the 1303 around 2000, not the original owner! The break in for the Yaris was after changing front discs an pads.

Edited February 13, 2017 by WesBrooks

[Soren Frimodt]

Very well described Wes, I think you hit the nail on the heat right there, the feeling and consistency is so vastly different on the two systems, that its actually very hard to compare the two.

And to add to that, bigger brakes does mean shorter stopping distance, even if the stock ones can block the wheel, how come? Well the initial bite of the brakes takes care of a lot of the deceleration, back when I used to Supermoto a lot, bigger discs in the front really did reduce lap time, also aided of course by the fact that you could trust your braking points lap after lap. But obviously the bigger brakes the more delicate your inputs has to be

[Bandog]

Soren, I also used to ride supermotard, I had a 2006 ktm 450 exc, with the rims and gearing changed and Bridgestone 010 sticky stuff. Those brakes as standard specified 5.1 dot motorex fluid in the tiny master cylinder, and little single wavy disk. Obviously expected things to get hot! 

Soon (very soon)  failed me on the local track, with more curve than straight, so lots of braking. Very tiring. Soon had them fading to non existence. Never, ever had a problem on loose stuff. 

Enduro, nick, locking up wheels, both front and rear, is an extremely common occurance. I won't be losing any sleep, if I have any problems at all, I might book a driving lesson with BSM 

[Soren Frimodt]

30 minutes ago, Bandog said:

Soren, I also used to ride supermotard, I had a 2006 ktm 450 exc, with the rims and gearing changed and Bridgestone 010 sticky stuff. Those brakes as standard specified 5.1 dot motorex fluid in the tiny master cylinder, and little single wavy disk. Obviously expected things to get hot! 

Soon (very soon)  failed me on the local track, with more curve than straight, so lots of braking. Very tiring. Soon had them fading to non existence. Never, ever had a problem on loose stuff. 

Cool, great fun right? Offroading in a 4x4 doesn't come anywhere near in fun factor I must admit, however it hurts less, cost less and you can be more creative with building stuff yourself. Okay thats a bit newer and smaller than what I used to ride (LC4 620) And it has a somewhat decent sized mastercylinder, we just used to space out the caliper and fit a 320mm disc  

And yeah locking up the wheels is a huge advantage in the dirt because you create a burm for the wheel to push against. Very scary at first, but it works really well  

[Bandog]

Leap of faith, like sliding the back into tarmac corners. Watch out for those tricky high sides though 

Snagger, sorry for the sarcasm, I think your a good bloke. But it's really only theory, and possibly not noticeable to most drivers. I think it's splitting the atom rhetoric. I was only commenting on how big the brakes are, and I won't be spending heaps on a disc brake conversion any time soon. 

[Snagger]

No problem!  I can see that you get my point by the way the conversation went - big brakes soaking up the heat on the track... well, that's not where SIIIs spend much time! Like I said, discs do make maintenance considerably easier and do give finer control, which Wes also mentioned.  But they don't really warrant spending thousands on in the hope they will make much improvement to stopping distances over a well maintained drum system for the likes of us.  It's shocking when you see what some people pay for the kits.

[Bandog]

I would actually one day want to convert the disks. It's got to last me a few years as is. Next big spend is winch and ball joints hubs etc. Was going to bite the bullet and get the bronze ones in dingocroft 

[garrycol]

Disks dont give better braking they give more reliable and consistent braking - plus they still work after you have just forded a river.

[Bandog]

My old pal who is 70 has shown me a chart for towing capacity from the 1970s, provided by a company called indespension. It shows a comparison chart for land rover series towing weight capacity. Highest was the 6 cylinder because of the brakes 

[Snagger]

That's misleading.  The brakes on the 6 cylinder are not the reason it has the highest capacity.

As I said before, the bigger brakes will just increase propensity to skid unless they tyres have more grip.  An 88" has lower tow capacity because of its lower weight, which affects towing stability and maximum braking effort.  To use bigger brakes for more retardation, you also need to increase tyre grip.  Towing a trailer isn't going to do that; it increases the mass to be stopped without increasing grip through weight on the tyres.

[Bandog]

So that 6 banger, 2.6 rover lump and a Salisbury axle make all the difference then?  Can't really see it being much less weight than a 200 tdi really. I have power steering and a whole heap of other weight including military bumper. 

[Snagger]

Still missing 21" of wheel base, with the directional stability that gives when towing, about 10" of rear overhang, the weight of those lengths of chassis and body, the weight of the seats and body structure.  That's a lot more influence than an MoD bumper.  And I suspect the 2.6 engine is heavier than a Tdi, too.  As for the power steering, which you have now mentioned twice as somehow affecting braking ability, I don't see its relevance at all.  It's a good mod, but makes no difference to retardation.

[FridgeFreezer]

Can confirm 2.6 I6 weighs as much as the moon.

The 6cyl brakes were also the (similarly powered) Stage 1 V8 brakes, I expect it's down to having enough power to get up to speed more quickly so need to stop from higher speed more often - in other words, big brakes = keep stopping repeatedly for longer under more load rather than outright stopping power.

Discs are still better though. Sorry but it's true.