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My camper is an 86. I'm going to replace the rotors, pads and calipers. Are these trucks 1 ton? What is the model? I measured the rotors on the truck, and got 10". Turns out there are 2 sizes, 9.75" and 10.11". I'm guessing i have the larger ones.

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10 1/8" by 1" thick (just a hair under) assuming you've got the 5 lug fronts. 4.35" bolt circle. Wagner # BD60804, Bendix PRT1365. Centric 12144035

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You had better take it with you the listings suck. 9.85 is a 10" listing The 11" were on one ton hubs only and if I remember they were bolted to the hubs with 6 or maybe 8 8MM bolts and the hub has to come off to replace the rotor.

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4.5"?

Bolt circle on all the rotor spec sheets I've seen list the rotor as having 5 bolts on a 4 21/64" bolt-circle (4.3") i.e. 110 mm. Bolt circle on the rotor used for mounting to the hub is not the same as the bolt circle for the wheel mounting. Wheel lug circle is 4.5". I am closely acquainted with the 5 bolt mounting circles. I had to drill out some 5 lug rotors to fit 6 bolt hubs I installed on a 1978 Chinook. I was fooling around with various rotors. The OEM 1978 Chinook rotors with five bolts are on a 4.1" bolt circle. The later 5 bolt rotors have a 4.3" bolt circle.

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A few photos of what I'm referring too. The 1986 HD brake set-up for 1 tons and RVs has rotors held on five 10 mm bolts on a 4.3" circle. Roughly equivalent to SAE 7/16" bolts.

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What a butcher job that is!

It works fine. There's no "butchering" here. Everything turns true (checked with a dial indicator). Grade 8 bolts holding the rotor and it's shimmed with hardened spacers. I'm waiting for someone to show a better way to put the 1 ton, 6 lug hubs from a 1987 dually onto the front of a 1978 Chinook. So far - going by the Net searches I've done - I'm the only one that's done it. The original rotors with 5 mounting holes have to be used and the 6 lug hubs have 6 mounting holes for the rotor. Only way I can come up with to do it - is just as shown in the photos. Original brake rotors and double-piston calipers retained. It seems to be impossible to fit the bigger single-piston calipers and 6 lug rotors on the front end of a 1978 with coil spring suspension.

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It does look to be the best possible placement of the new holes. Four of the 6 screws are completely separate from any weakening from the old holes and it's on the front of a Chinook which is relatively light.

Linda S

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They do make 5 to 6 bolt adaptors for that, The spindle is the same size so there is really is no gain to the large hub and as you say you can't go up in rotor size any way.

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They do make 5 to 6 bolt adaptors for that, The spindle is the same size so there is really is no gain to the large hub and as you say you can't go up in rotor size any way.

Yes and the adapters cost a small fortune, place the wheel further out, and have the wheels running on smaller lugs.. Last I checked over a year ago - the place in Bloomington California wanted over $400 for a pair of those AT6714F adapters shipped to my house. Also they had NONE in stock. A few months ago I checked their URL and the link no longer exists.

In my case - I already had the 6 lug hubs and retrofitting them cost me nothing but time. If I was worried about using up my time-on-earth with such things - I would not own an old Toyota in the first place. Drilling the 5 lug rotors for 6 holes to fit the hubs hurts nothing. No weight bearing there either.

If you've done a better job on such a conversion - I'd like to see it.

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It makes me a bit nervous seeing extra holes drilled in a part, especially something critical like a brake component.

Doesn't make me nervous at all. Guess you've never seen brake rotors drilled with many holes to make them lighter and cooler for racing? In this case - no weight bearing is involved. Just holding the rotor to the hub. Not a very big job on a Chinook. The absolute worse thing that could happen is what? I've had many a brake rotor break/crack over the years that was stock. Nothing bad happened. Just a thumping/pulsating in the brake pedal and a warning I had to fix it pretty soon. Maybe if this vehicle was an early 60s or older with a single-master-cylinder braking system I'd have a little extra concern. If I had to weight vehicle equipment concerns and compared my drilled out rotors -to let's say a 6000 lb. RV built on a Toyota mini-truck - the latter would be more concern to me.

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DIY brake mods still make me nervous. :)

Rotor_BigCrack.jpg

I've had stock, full-thickness rotors crack just as bad. That rotor in your photo has obviously been severely overheated. I guess you get "nervous" more easily then me. Besides -I've got no extra holes in the brake-surface area where the high heat can generate.

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You're the one who brought up drilled rotors, not me.

Yes and I' saying I've see non-drilled rotors crack just as bad as the one in the photo - when overheated.

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Yea it looks a little blacksmithy, but there 4 bolts in solid metal and the shear strength of an 8.8 grade 10mm bolt is over 3 tons. I don't think the brake caliper can exert over 12 tons of force on the rotor with out ripping the linings off the pads or destroying the rotor itself.

JD also says it runs true so again a bit blacksmithy but done within the limits of the design he was working with.

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Your motor home it's some thing I would not except on mine.

I must be losing my grasp of American-English. I have no idea what that comment means.

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  • 2 weeks later...

The camper brakes must be odd balls, I deal with napa and they normally have zero trouble locating stuff. The rotors are 10.11". The pads were tricky to find. All going back together Monday. New calipers, flex lines, rotors and pads.

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So you finally managed to get the parts from NAPA? How about listing the part numbers here to help others (and their local NAPA)!! :)

NAPA only sells one rotor to fit the 1986 1 ton. 10 1/8" diameter with a 4.3 bolt circle. It's the same as what I posted earlier - i.e. "10 1/8" by 1" thick (just a hair under) assuming you've got the 5 lug fronts. 4.35" bolt circle."

Wagner # BD60804, Bendix PRT1365. Centric 12144035. NAPA # 4886027. $40 at my local NAPA. MUCH cheaper at $17 from Rock Auto and every bit the same quality.

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Not exactly on topic but I will never buy another Centric part again. Bought brakes shoes for my Nissan Sunrader and they did not fit. Rock Auto would have refunded my money but they are heavy and shipping was almost the same as the refund. Called Centric and gave them the part number and they insisted they were the right size. NOT. Had a couple other guys look at it for me too and they agreed wrong size.

Linda S

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Not exactly on topic but I will never buy another Centric part again. Bought brakes shoes for my Nissan Sunrader and they did not fit. Rock Auto would have refunded my money but they are heavy and shipping was almost the same as the refund. Called Centric and gave them the part number and they insisted they were the right size. NOT. Had a couple other guys look at it for me too and they agreed wrong size.

Linda S

I could say the same for just about every brand of auto part sold. Some time or another I've gotten parts going by a catalog listing and the part was incorrect. If I quit each company for that happening just one time - there would be no companies left to buy from. Happened to me several times buying OEM parts too. One nice thing about Centric is they often post full spec sheets on the parts they sell. Pretty hard to go wrong that way unless you don't get to see the old part first.

I'm surprised that Rock was going to charge you shipping. Their policy is - if a part was listed in their catalog by error - they pay the full shipping charges back. They've done if for me several times for large parts. For small parts they've just given me a refund and let me keep the parts too.

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Except Centric insisted that the part was correct and I was wrong. That's why I called the company. I expected them to say it was a mistake but no way. I got stuck with them.

Linda S

I had a similar problem a few months ago with a Centric master cylinder for a 2001 Kia Sportage. Winds up that Kia used three different master cylinders in one model year. After some lengthy research -I found that none of the ones Centric stocked would work. They only had two of the three. I called Rock Auto and they just gave me the new master cylinder I already had - for free. Told me to keep it and gave me a full refund. Still sitting here in a box. Then they sent me another brand that was correct and I paid for that. Just a few bucks more. I'm not going to fault on that. They don't write the parts catalogs. If I had done my own thorough research and gone to Kia's Website - I'd found out how problematic getting a correct master cylinder was. I DO fault Centric because they should of mentioned they only carried two possibilities and not all three. Note - I've also had similar issues with parts for Dodge trucks and vans - even from the dealer. With many HD 90s Dodge trucks - there is no way to know for sure what brake parts are used until you inspect the old ones and then match them up.

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I'll post the part #s on Monday when I pick them up.

Kahuna

If you NAPA dealer had any trouble looking up the parts - it is because the person was ill-informed. NAPA only sells one rotor to fit your motorhome.

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The problem comes up with built date and 1 ton hubs. Granted an 86 should have the smaller rotor but not all 87 had big rotors. NAPA does have both rotors and it can be confusing for those that don't know that is why it is a good ideal to take the old rotor with you unless you like making two trips.

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The problem comes up with built date and 1 ton hubs. Granted an 86 should have the smaller rotor but not all 87 had big rotors. NAPA does have both rotors and it can be confusing for those that don't know that is why it is a good ideal to take the old rotor with you unless you like making two trips.

The NAPA catalogs show only one rotor choice for a 1986 model year Toyota cab & chassis RWD truck that came as 1 ton HD. No grey area, no alternate choices. I suspect whoever was looking up parts for the person who posted here was not real good with the parts books. I have all the NAPA brake-parts books here at my house. The Raybestos # 48869027 is the only choice and is a Chinese rotor from Raybestos and branded by NAPA. Also sold as . . Raybestos # 96027R, AC Delco 18A317, Wagner BD60804, CarQuest 3270, PartsMaster 60804, Autozone 96027R, Toyota 4351235180, etc. Same rotor as used in 85-95 Dynas, 83-88 Hi-Aces, 83-97 Hi-Luxs, 84-88 four cylinder pickups with HD brakes in the USA, and in some 88-93 V6 1 ton cab and chassis configurations.

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  • 5 weeks later...

between 75 and 83 they did use on pick-ups (C&C) w/"K" type calipers they seem to be odd and rare --

raybestos - super stop front pads= # SSD197 semi metalic

nappa = # TS7120

raybestus = # PGD 197

Edited by vert
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