Have a cat 3306c in an autocar dump truck. Jake brakes are not working, I pulled the valve cover and all electrical connections are good. The solenoids are working so I suspect something mechanical. Id like to order a tune up kit but I'm not having any luck finding one online. Is there somewhere online to order a kit? The Jake brakes is a 336a. Also if anyone has any pointers on what to look for it would be appreciated. This is my first time messing with Jake brakes.
You checked solenoids individually for operation? Did you check clutch micro switch? Are jakes getting proper oil psi? There isn't too much that goes wrong with engine brakes, If both are not operating then it's something else, power/oil psi. Normally jakes just get weak, which can also be aerated oil. Tune-up parts for any jakes no matter the brand of engine are a dealer item only--in the case of things that are yellow--Cat only or Cat dealer.
Yes, clutch switch is working properly, the switch on the fuel pump for the throttle is working and both solenoids are engaging. Engine oil psi cold is around 70. Warm it's around 25-30 at idle. Do the jakes have any type of boring seals or something of that nature that could make them leak and loose pressure?
Not really-Solenoids have O-rings. How do you know if oil is reaching jakes? Remove covers and test jakes while running.
Isnt there a screen on the solenoids could be plugged up
Yes there is, only in thing is it will cause a weak very slow to energize issue, if screens are that plugged there's issues else where.
Could old thinned oil cause the problem. This truck is new to me and who knows when the last time the oil was changed. I drove it home over a 3 hr ride without issues. Oil level was full and pressure stayed good. I'm about to do a full service on it I was just wanting to get the jakes working before I did
I pulled the solenoids, screens are clean looks like the oil is getting to the top of the engine.
There is a small round hole in the centre of the hex on top of the solenoid with the engine warm and idling push the plunger in the centre of the hex down with a small screwdriver or pick. The Jake brake head should activate. Look for oil leaks with them activated.
Oh My! that engine has sat for some time. If you pulled the solenoids did the little green & white o-rings on those come out in one piece? {not swollen/distorted}. As mekanik said there is a test port on top of solenoid, when depressed it will/can shoot oil straight up so keep your head back. In moisture rich climates engines will collect condensation in the upper end and rust is the by product, even living in a oil soaked environment. * A generic view of jake operation.
Yes the rings looked ok. I've pushed the the hex on top of the solenoids to push them down. Still no activation. I changed the oil and filter and still not working
Pull the solenoids out-it will be messy-start and shut off asap to see if oil is reaching housings. There is the possibility oil is getting there--but the oil control valves in jakes are stuck.
I pulled the solenoids and there is oil getting up there but seemed like a weak stream
Interesting--problem is--I can't see it from here, nor can anyone else. Need to find a oiling diagram for rifles that feed the top end, next then verify it has low oil psi/flow. When you tested the jakes with engine running how high was the rpm at that point of testing? What was oil psi on the dash gauge with solenoids removed?
It was just at idle. But I put everything back together and went up the road at around 1500-2000 RPM trying them and no change. I might pull the control valves out and see if they might be stuck. It would make since seeing how rusty the outside of the Jakes are. Maybe they just aren't letting enough oil in. I'm not sure
They should activate at low rpm but if worn it takes more psi. The housings on removal should be full of oil through the circuitry. Check to make sure all spots where housings were drilled for oil rifles, that the galley plugs are in place. It is not uncommon for galley plugs {allen head} 1/16 thread in's to fall out. Detroit Series 60 790/795 jakes had a issue with that. Flip the jakes on and check engine light would come on because it dropped the oil psi. Plugs were commonly found on magnetic oil drain plug.
I have a good bit of oil at the back of the head but seems like it's not making it all the way across the rockers. Is there some kind of deal on these 3306s in the rocker shaft?
Seal
Here is a link to the parts manual: https://drive.google.com/file/d/1nO0D1PXNha86QoA8JC4p1iIOezWNStNV/view?usp=sharing The oil supply tubes items 1 and 4 on page 3 are the O-Rings leaking with the engine idling? Here is a link to the installation manual: https://drive.google.com/file/d/1cKK7njldAtS32Re-cw3fVw_T_tBNEFWI/view?usp=sharing
Yea it's leaking while idling. I wish I could upload a video here but basically at the back of the head the oil is coming up and spraying back down on the head under the rocker shaft. The only place I see oil is at the back. Doesn't look like the rest of the head is getting good lubrication
Ah Ha said the blind man!
You can't. Upload the video to something like YT and link it.
I attached a YouTube video. It was as good as I could get trying to take in and crank the truck by myself
Well that there outa be the lack of erl pressure to turn on the popcorn poppers
^^^^^
I'm going to pull the Jake off this weekend to see if it's a seal, cracked Jake housing, missing plug on the bottom or something else. I will post an update just so it's on here. Everyone I talked to local has never seen a 3306 with Jakes on it before and this is my first time messing with one of these engines so maybe it will help someone else in the future
3306 with jakes is rare--I've seen one only. And those are more than likely obsolete.
I've noticed I can't find much on them. But there is a lot of the 336a Jakes for sale online.
I think you have a broken rocker shaft. You will need to pull the jake head and have a look.
I think he said he was going to do that. Yes--there are 336 jakes for sale, but one issue with them is it is not a strong jake. The ones listed are from old core engines, and the reason so many for sale is the fact the 3306 is a old design and not allot of interest. Same for 346 jake used on the 3406 B model, allot available because the engine those were on has a hole in it.
I believe I found the problem
I only give a like because-problem found, rocker stands for 3406 A/B although rare have been known to crack also.
It looks to me like whoever put the Jakes on last did so with a hammer. The supply tube pushed down on that fitting and bent it. Then broke the mount
The guy that installed the Jake head did not get the oil supply tube lined up with the supply port and did all that damage when he torqued it down..
Which leads to--how long has it been running that way? Plus he obviously just throwed the covers on and never checked his work with it running/testing.
I bet the Jake Brake worked before he fixed it.
Here's the problem----what was he in there for? May not have had anything to do with jake. What else could be a issue?
Head gasket? 3306 with a Jake was prone to head gasket failure.
I'm really not sure, I can't find anything else wrong. The truck was running fine I purchased it and it made a 3 hr trip like this. No telling how long it was ran like this before I purchased it. No engine noise, no blowby, no smoke and fired right up even on the cold days. The only reason I tore into it was trying to find out why the Jakes didn't work.
Well--correct it and drive it--if you have no records of repairs with purchase it's a guess.
I've got all the parts I need except for this oil supply fitting. If anyone has a lead on where to find one that would be great. I've looked online but again can't find much
Again---parts for Jacobs--especially the hard parts are {dealer} {Cat} items. Jacobs has a strict policy about vendors. Buy the way you never said what year this A-Car or 3306 is, because Jacobs has discontinued many items older that 30 years. You're more than likely going to end up at Cat.
It's a 1995. I'll be calling cat Monday to see if they can get it. If not I guess I'll have to come up with something else.
You can also try Jacobs help line. Thing is, there is probably several on shelves at dealers across the country.
A machinist could make that in short order. If you weren't so far from here I would make that and the rocker shaft pedestal for you. Did the oil tube that goes into the fitting survive?
You could on short notice because you're not a machine shop. This day and age 3 to 4 weeks.
For some reason that fitting looks familar since i didn't do much work on trucks i'm thinking cat dealer might be able to help especially if they have sim parts on micro fisch
if it is truly 1995 it ought to be in SIS. Post an engine Serial Number. You might be able to go to Cat with a Part Number if the engine was originally built with Jakes.
I used a 9TL.
It's what I was saying, In order to be a vendor for Jacobs---it has to be either a Cat, Cummins or Detroit, Mack dealer. Engine brakes didn't come factory installed till about 1990. And even then those were all mainstream engines that would commonly be used in a truck application with a high build/manufacture rate, 3406, 855 Cummins, V-series Detroit. * As I noted before in a thread, I use to work at a shop in the Emerald City during a winter. That shop had the contract for PacBrake --PacBrake came alive when the jake patent ran out. I had to go to Richmond BC.--PacBrake HQ, for training to cert for installing PacBrake's on 3406 A/B Cat engines----being installed at Kenworth plant. Back in those years when a truck was ordered it was specified with or without engine brakes. All engines were on roller gurneys, all tools supplied, air opps from above, boxes and boxes of PacBrakes on carts. We took turns one guy one week another the next starting in afternoon for next days production run. Most I ever installed was 5 complete sets, it's the most anyone could do in that time period of a shift. Mind you there was a guy the next room over installing Jacobs brand. The average was 2 to 3 a night. But it wasn't till after about 1990 I guess that engine brakes became standard equipment out of the factory.
Begs the question whats better the pac brake or genuine Jake
The PacBrake then was a copy of the Jacobs 346--basically the same identical brake. Jacobs did build another model the 349A- a stronger jake using more valving control. The issue with all Cat engines of those design including 3306/3406 was all injection was through that massively expensive pump hanging on the side. So no injector lever for jake operation {timing}, that's why that poor old ugly tan engine hammered out of a piece of tin {The Cummins 855} had the best brake horse power of all engines back then, it all has to do with timing valve openings. The 349A had IIRC two extra oil control valves that were signaled from other cylinder firing order that opened the exhaust valves closer to TDC. But there are NO parts available and the 349 is obsolete, plus it had a tendency to wear the bore in the master piston. * Are PacBrakes good?---Yes.
After calling the several different Cat places and a local Peterbilt dealership I believe we have figured out that the part number I need for the oil supply fitting is 7E-4176. Unfortunately cat wants $500.00 for the little fitting and are saying it will be a 54 day lead time
I will probably need the oil tube as well. It's a little damaged on the end
Know where any d250e are being scrapped They might have what you need also we had a lot of cement trucks around here with that engine
There should be a machine shop in your area that could produce those. Although probably as much. Did you try calling Jacobs directly? Salvage yard will want to sell complete units.
I got the truck back together and running good, Jakes work properly now. I went ahead and replaced the rocker shaft as it had a bad spot where the broken stand was. We managed to get the oil supply fitting straightened out with some heat.