rx1jim
New member
Here is some info. I want to pass on about the rebuilding/repair of the SRX water pump. I have been working on several SRX 600 and 700 engines, some to reclaim parts from and 3 I am rebuilding. Here is what I have learened:
1. Source of leaks: When coolant is observed coming from the weep hole under the engine, directly below the water put, often the ceramic mechanical seal is blamed as the source of the problem. There is a rubber coated metal washer under the bolt that holds on the impeller. This washer can be the source leaks and I beleive is many times (buy not always) the actual source of the leak which is blamed on the ceramic mechanical seal. NEVER reuse this washer since the rubber will take a "set" and not seal properly if reused. As an extra layer of protection, members of this site have taught me to use green (low strength) loctite on the impeller shaft splines. The loctite acts as a an additional seal and also keeps the impeller from moving against the rubber seal washer whle it rotates. If you have a leak, I suggest you replace the rubber seal washer and test the engine. If the leak stops then it was the washer and you saved yourself a lot of work. If it still leaks, then the engine must be removed in order to replace the ceramic mechanical seal.
2. Removing the impeller. The impeller can be a real pain to remove if there has been a coolant leak for some time. The impeller shaft is steel so it rusts pretty easily, the rust in the spline area locks the impeller in place. I have tried applying heat and penetrating oil then try to gently pry the impeller off. There is no good place to get a small pry lever under the impeller. What works for me, even on a severely corroded impeller shaft is: remove the impaller bolt and the rubber coated seal washer. Get a 6mm bolt which is long enough to bottom out in the impeller shaft but not have the head come in contact with the impeller. Grab one of the impeller vanes (preferably two vanes but you will need a helper) with a pliers. I wrapped the jaws of the pliers with electrical tape so as to not gouge the aluminum impeller vanes. Hold the vanes firmly trying to pull the impeller off while striking the 6 mm bolt with a brass hammer. I find 2-3 sharp ( but not killer) blows with the hammer is enough to get the impeller right off.
3. Impeller shaft and oil seal. The impeller shaft is also the drive shaft for the oil pump. Right behind the mechanical water pump seal is an oil seal. This seal provide the seal between the inside of the engine and the impeller shaft. Once you remove the mechanical seal, carefully inspect the impeller shaft in the area of the oil seal. If there was a coolant leak for an extended period of time, the impeller shaft will be corroded and may be corroded enough to make the oil seal ineffective. In this case, you will need to replace the impeller shaft and oil seal. To remove the impeller shaft there is a snap ring holding in a small ball bearing and the impeller shaft. Be careful when removingthe snap ring, don't drag it out of the water pump seal/oil seal bore. Be careful not to scartch this bore or else the oil seal and the mechanical water pump seal will leak throughthe scratch/gouge. I just bought a pair of internal snal ring pliers which allows the removal of snap rings from deep cavities from Summit Racing, it is perfect for this snap ring.
4. Mechanical water pump seal. To remove the old seal, use a small screwdriver or small blunt chisel to push the outer flange towards the center. I work around the seal to collapse it towards the center and release it from the bore it is pressed in to. Be very careful to not bugger up the crankcase. Take your time to collapse the seal the pull it out, I use two needle nose pliers to pull it out once it is free from the bore. The new seal has a blue ring of sealer on it. Be sure the bore in the case is clean and gouge free then install the seal using an arbor or deep socket to push the seal in place. You want to apply pressure to the flange around the outside of the seal and put it in square. I machined an arbor which applies pressure to the outer flange while centering the seal in the arbor.
The water pump impeller spins at a pretty high speed. The drive gear on the crankshaft has 10 teeth and the water pump/oil pump drive shaft has 12 teeth. At 8000 RPM engine speed, the impeller is spinning at about 6000 RPM so it does not have an easy life!! The tight the fit of the impeller to the drive shaft the better, hence the use of the green loctite.
If you are perorming a complete engine rebuild, it is well worth spending the time and money to replace the water pump seals. For the small extra time and money it is a good investment
1. Source of leaks: When coolant is observed coming from the weep hole under the engine, directly below the water put, often the ceramic mechanical seal is blamed as the source of the problem. There is a rubber coated metal washer under the bolt that holds on the impeller. This washer can be the source leaks and I beleive is many times (buy not always) the actual source of the leak which is blamed on the ceramic mechanical seal. NEVER reuse this washer since the rubber will take a "set" and not seal properly if reused. As an extra layer of protection, members of this site have taught me to use green (low strength) loctite on the impeller shaft splines. The loctite acts as a an additional seal and also keeps the impeller from moving against the rubber seal washer whle it rotates. If you have a leak, I suggest you replace the rubber seal washer and test the engine. If the leak stops then it was the washer and you saved yourself a lot of work. If it still leaks, then the engine must be removed in order to replace the ceramic mechanical seal.
2. Removing the impeller. The impeller can be a real pain to remove if there has been a coolant leak for some time. The impeller shaft is steel so it rusts pretty easily, the rust in the spline area locks the impeller in place. I have tried applying heat and penetrating oil then try to gently pry the impeller off. There is no good place to get a small pry lever under the impeller. What works for me, even on a severely corroded impeller shaft is: remove the impaller bolt and the rubber coated seal washer. Get a 6mm bolt which is long enough to bottom out in the impeller shaft but not have the head come in contact with the impeller. Grab one of the impeller vanes (preferably two vanes but you will need a helper) with a pliers. I wrapped the jaws of the pliers with electrical tape so as to not gouge the aluminum impeller vanes. Hold the vanes firmly trying to pull the impeller off while striking the 6 mm bolt with a brass hammer. I find 2-3 sharp ( but not killer) blows with the hammer is enough to get the impeller right off.
3. Impeller shaft and oil seal. The impeller shaft is also the drive shaft for the oil pump. Right behind the mechanical water pump seal is an oil seal. This seal provide the seal between the inside of the engine and the impeller shaft. Once you remove the mechanical seal, carefully inspect the impeller shaft in the area of the oil seal. If there was a coolant leak for an extended period of time, the impeller shaft will be corroded and may be corroded enough to make the oil seal ineffective. In this case, you will need to replace the impeller shaft and oil seal. To remove the impeller shaft there is a snap ring holding in a small ball bearing and the impeller shaft. Be careful when removingthe snap ring, don't drag it out of the water pump seal/oil seal bore. Be careful not to scartch this bore or else the oil seal and the mechanical water pump seal will leak throughthe scratch/gouge. I just bought a pair of internal snal ring pliers which allows the removal of snap rings from deep cavities from Summit Racing, it is perfect for this snap ring.
4. Mechanical water pump seal. To remove the old seal, use a small screwdriver or small blunt chisel to push the outer flange towards the center. I work around the seal to collapse it towards the center and release it from the bore it is pressed in to. Be very careful to not bugger up the crankcase. Take your time to collapse the seal the pull it out, I use two needle nose pliers to pull it out once it is free from the bore. The new seal has a blue ring of sealer on it. Be sure the bore in the case is clean and gouge free then install the seal using an arbor or deep socket to push the seal in place. You want to apply pressure to the flange around the outside of the seal and put it in square. I machined an arbor which applies pressure to the outer flange while centering the seal in the arbor.
The water pump impeller spins at a pretty high speed. The drive gear on the crankshaft has 10 teeth and the water pump/oil pump drive shaft has 12 teeth. At 8000 RPM engine speed, the impeller is spinning at about 6000 RPM so it does not have an easy life!! The tight the fit of the impeller to the drive shaft the better, hence the use of the green loctite.
If you are perorming a complete engine rebuild, it is well worth spending the time and money to replace the water pump seals. For the small extra time and money it is a good investment
Great info man thanks alot im new to yamaha sleds and the people on this forum have been very helpful. Its guys like you that make wrenching on unfamiliar things a little less complicated and a lot more fun thanks again