Birty Dastards Jeep Club
Tech Forum => Workshop => Topic started by: Brynjaminjones on April 18, 2014, 07:33:36 AM
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Morning Chaps
A long journey in an overloaded XJ highlighted the fact that I shouldn't really go any longer without sorting the front brakes out. After overheating them in a sudden stop there was definite grinding when braking reasonably hard, which didn't go away until I drove very carefully for about an hour to let them cool down! :icon_eek:
The front discs have been warped for a good while, so I know I need discs and pads. What ones should I go for - I'd like good ones but don't want to break the bank. I've not looked at what's out there yet, but am sure you lot know your stuff!
Is there anything else I should look out for when replacing them, and anything else I should replace?
Cheers!
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Easy answer Is one call to Lighthouse.
Or e bay for all the bits from whoever is selling at a price that suits your wallet
Far more time consuming is a WJ conversion and the transit van conversion for the rear .........
As it's a DD and you want to make it safe......at a price you can afford. The first options would be my advice :icon_super:
Tis also easy and a bonding exercise for you and your rig. :icon_biggrin:
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Excellent, thanks for that. I'll be giving them a call on Tuesday (I made the mistake of calling them around Christmas and it didn't go down too well, so I definitely won't be calling them on a bank holiday!) :003:
I honestly can't wait until I have brakes that don't make me want to avoid slowing down wherever possible!!
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Get discs the cheapest place possible and then buy some EBC Greenstuff pads. I had this for a while and was impressed, only got one case of brake fade when driving enthusiastically to Seven Sisters the scenic route over Welsh Mountains. Yellow stuff pads might help if you are really pushing it but it is a Jeep not a Porsche.
Follow this Pirate 4x4 guide and you should have good breaking without costing £££.
Bedding-in Brake Pads
When new brake pads are installed, they should be "bedded-in". Bedding-in brake pads is a process of breaking them in before severe use, similar to the way an engine or set of gears must be broken in.
To perform the “break-in”, follow the steps listed below:
Step 1: Make 10 stops from 30 mph (50 kph) down to about 10 mph (15 kph) using moderate braking pressure and allowing approximately 30 seconds between stops for cooling. Do not drag your pads during these stops. After the 10th stop, allow 15 minutes for your braking system to cool down.
Step 2: Make 5 consecutive stops from 50 mph (80 kph) down to 10 mph (15 kph). After the 5th stop, allow your braking system to cool for approximately 30 minutes.
This completes the “break-in” of the pads to the rotor surface. Full seating of new brake pads normally occurs within 1000 miles.
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Awesome, I had a feeling you'd be knowledgeable about this!
I think I'll go for the Greenstuff ones. I do generally brake gently, but when I first passed my test I didn't quite appreciate how much an automatic can eat brakes, which is probably why they warped!
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get the pads and disks off ebay as they will be cheaper than lightys, or try mill autos to see what they have. if your brakes are binding then replace the pistons and seals for new. not a hard job by any means but at least you will know that you will have good brakes. dont forget you might as well pull fresh brake fluid through as well
not pushing a sale in any aspect but i have two brand new calipers (fully refurbished) sitting in the garage somewhere just need pads. I'm in no rush to sell at the moment but if your interested make me a reasonable offer.
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I also have standard discs with ebc green stuff pads bought from 4play jeep. Improved stopping power that didn't break the bank. I think the pads were about £80. Probably worth changing the brake fluid at the same time imho.
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Excellent, thanks guys. You're right, I think I ought to change the fluid too - last time the mechanic looked at it his comment was "hmm, when was that last changed!?"
Dave, how likely do you think it is that I'll need to change the calipers? Without wanting to sound stupid can you explain to me what would cause them to need to be replaced?
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if the caliper pistons are sticking and the pads won't release of the disks.
then you need to replace the piston in the caliper.
it think you need to replace the fluid as if it's not been done wile you've owned it. then it needs doing
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The pistons become slightly oval with prolonged heat and then stick.
A piston and the rubber boot come as a kit and are a tenner or so, and easy to replace when you take the calipers to the bench.
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:iagree:
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Great, thanks for the advice. I'm not aware that my brakes have been binding at all, but is there any chance that they could have been doing so without me realising?
I'll ask my mechanic if he'd recommend replacing the calipers or not before I make any decisions!
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Chances are that if they got hot they would have 'bound'
All four of the brakes on my ZJ were smoking and bound on when I stopped just before Breakout last year.......had to wait 30 mins for them to cool....
That was due to overloading ......towing the 1 tonne on its trailer up and down hills outside Bristol,
When it was only used to the Flatlands of East Anglia :hysterical:
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For brakes I always upgrade, no pussy cardboard for me!!!
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to be honest Abe you only need a piston kit which will be piston and seals, which i think your looking around the £20 mark for the kit. cook the brakes big style and the pistons shape warps.
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As far as I'm aware I've never cooked them big time - I engine brake whenever possible around the steep hills in the lanes, and am always cautious not to repeatedly brake hard. I will look like into it though.
As for discs, would these do the trick? http://m.ebay.co.uk/itm/131162594055?nav=WATCHING_ACTIVE
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The main cause of warping the discs is by keeping your foot on the brakes when stationary instead of using the handbrake.
Town driving, having to stop at lights and keeping your foot on the brake instead of using the handbrake is the biggest culprit.
I have always been a big fan of Brembo discs and pads but that's personal choice.
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brake pads are the sacrificail part of the braking system so these wear out way before any disk, the harder the pad the more wear on the disk and the higher risk of warpage. the warpage is dependant on the make of disk being used.
those are cheap enough and will get you going again. might have to swap them in a couple of years
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As far as I'm aware I've never cooked them big time
I wouldn't be to sure about that looking like this, it's not a 'kin horse & cart yer driving :hysterical:
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:hysterical: :hysterical: :hysterical: :hysterical:
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I hope you're not laughing at how I always dress! :icon_winkle:
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The main cause of warping the discs is by keeping your foot on the brakes when stationary instead of using the handbrake.
Town driving, having to stop at lights and keeping your foot on the brake instead of using the handbrake is the biggest culprit.
I have always been a big fan of Brembo discs and pads but that's personal choice.
Why would keeping your foot on the brakes while stationary warp your disks?
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:017: yes I am with the honourable ky on this
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:017: yes I am with the honourable ky on this
The curator has found following. Although relevant to early WJ's with other calipers, the cause 'might' be applicable to XJ's
All 1999-2002 Grand Cherokee WJ models built through May 10, 2002 came equipped with brake calipers made by Teves. They are black in color with an open-sided bracket design. Due to poor caliper centering, the Teves calipers caused the rotors to warp, a problem that has plagued Grand Cherokees.
Anorak back on the hook now :003:
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That sounds quite possible Dutch.
As for keeping your foot on the brake when stationary, I think I did read something about that once. There's a strong chance that I'm wrong, but I think the theory behind it was that leaving your foot on the brake after a hard stop, e.g. coming off a slip road then stopping at traffic lights, would prevent the heat under the pads from dissipating as well as the rest of the disc, causing a hot spot which could warp the disc.
This if from memory though, so feel free to correct me! :003:
Also, I've ordered the stuff now. I went for some EBC Greenstuff pads, plus some reasonably cheap discs on eBay from a seemingly decent seller. 8-)
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I've read the advice to take brakes off when stationary before but only for breaking new pads and discs in.
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LOOK !! Green, PINK (KY CREW) compound I don't care, it counts for shiet!! Brakes get HOT, brakes go to mud/water brakes hate it!!! Answer is to upgrade end of.
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My discs arrived today, so I need to start thinking about how to change them.
I could go to my mechanic and get him to do them, or see if he'll help me, but I'm also considering doing them at home.
Question time:
How do I replace them? I've found a guide and it looks simple, but I don't think I have anything to squeeze the piston back to put the new pads in - are there any tricks to doing this?
What tools do I need for everything?
Do I need anything else? Some places mention grease, and anti-squeal stuff, and I've also heard mention of de-greasing the discs before fitting.
Any advice that you lot have would be very useful! :003:
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I have done a few without any specialist tools,
Used a G clamp to push pistons in, after undoing the reservoir cap. Might not be the right way but its worked so far.
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Aerosol can of brake cleaner to get your mucky paw prints off the discs and any unwanted oil that gets everywhere when doing the job
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Copper grease to lube everything up and help avoid squeaks. I use a G clamp to compress brakes on the Jeep (other cars needs a special tool to turn the pistons - Jeep doesn't).
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Good choice bryn, you will notice the difference once they have been bedded in.
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take wheel off
undo two bolts holding caliper on
use pry bar to push caliper off disk
use a g clamp on old brake pad to push piston back into caliper
replace new pads
pull off brake disk
put on new brake disk
replace caliper and bolts
pump brake to seat pads
replace wheel
drive
time 1/2 hour to 45mins start to finish
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I like these simple instructions - cheers Dave! :icon_super:
I'm just waiting for these damn slow pads to arrive now...
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Call it a half day for the job both sides if you drink tea and like to clean stuff up before re-fitting like me.
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Yeah, I usually at least double quoted times to account for my tea/coffee drinking, getting distracted, and general uselessness. :003:
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if you want a hand i can help tomorrow (sunday) if that suits
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That would be great Dave - it just depends on whether or not the pads arrive today (which I somehow doubt they will!). I'll let you know if they do! 8-)
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When you've done the fronts it would be worth re-adjusting the rear shoes manually through the access hole. Then you'll have all brakes as they should be (until the rear auto adjusters don't auto adjust :icon_rolleyes:)
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Ok. Let me know the outcome. Since its lunch time i gather tje pads havent arrived
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The main cause of warping the discs is by keeping your foot on the brakes when stationary instead of using the handbrake.
Town driving, having to stop at lights and keeping your foot on the brake instead of using the handbrake is the biggest culprit.
I have always been a big fan of Brembo discs and pads but that's personal choice.
Why would keeping your foot on the brakes while stationary warp your disks?
The heat increases where the pad is holding the disc and creates a hot spot. We have it happen with our trucks that do city centre deliveries. Our mechanics explained it to me, I am just passing on there explanation.
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Ok. Let me know the outcome. Since its lunch time i gather tje pads havent arrived
Nope, I don't know why they're taking so long! :icon_sad:
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A disc rotating against the fiction material generates heat. A stationary hot disk with an applied friction material does not create heat as there is no heat generation taking place. The brake applied while stationary will act as a heat sink from the hot disk into the caliper and brake fluid. Warpage normally occurs when the brakes have been dragged and the colour of the disk has turned blue. A siezed piston is a classic cause for warping disks. Another is constantly dragging the brake from an auto, which normally happens on hilly roads.
I can only assume the drivers are dragging the brakes in town traffic if the trucks are autos.
When disks are below the recommended minimum excessive heat will also increase the chance of warpage, hence the design of vented disks and drilled holes.
But there again i dont know alot so will stand to be corrected
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The only thing I would add is to look where the pads ride on the carrier bracket. Over time the little grooves where the pads sit turn into big grooves. Not sure if it would ever cause an issue but I always welded mine up and filed them back down.
I do miss working on a newer Dana 30 front axle. It takes longer to get the wheels off then do the brakes. Never used a G clamp when replacing the pads or discs. I just cheated and jammed a screw driver between the disc and pads before removing the calipers. They were being tossed anyways so who cares about scratches.
Three bolts more and the wheel bearing and drive axle come out when things went wrong. Very easy system to work with and it would be great if it was beefier.
I run mine like a race car and stand on the brakes when stopped and never had an issue with warpage but maybe I am just lucky.
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I picked up some new pads today and have got this all done!
I struggled on the first wheel as I didn't have a G-clamp, and couldn't get the piston back in by levering it. I borrowed a clamp from someone else in the end though, and the second wheel took me 15 minutes! :icon_super:
I've not been out for a drive, but they seemed fine maneuvering around home!
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good man there
:icon_super: :icon_super:
http://www.ebay.co.uk/itm/6-150mm-Heavy-Duty-G-Clamp-Metal-Wood-Woodwork-Vice-/351045768651?pt=UK_Hand_Tools_Equipment&hash=item51bbf555cb
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I know, there really is no excuse for not having a clamp!
I took the Jeep for the first drive with the new brakes today, and they've absolutely transformed it! I knew they'd always been bit warped since I started driving it back in 2012, but I didn't know it was possible for them to be so smooth and quiet!
This is the happiest I've ever been with anything I've done with the Jeep - it's just so much nicer to drive now! :003: :003: :003: :icon_super: :icon_super:
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:greggmo: