This Lotus twin cam water pump was sent to Lotus Marques from an engine reconditioning workshop based in Sydney.
During the course of various telephone conversations it was established the pump belonged to a customer who is well known to us.
It appears this same customer purchased a water pump kit from the UK and did not receive comprehensive instructions on how to rebuild the pump successfully.
The photographs above are very useful when diagnosing why the freshly rebuilt pump has failed and allowed water to exit the weep hole.
Carefully examining the impellor, seal and bearing assembly reveals the following -
1) The brand new impellor blade tips have not been machined correctly when first manufactured.
2) Insufficient crush on the seal has allowed hot water to escape and enter the bearing where it has flushed out large amounts of grease.
3) Rust deposits on the bearing shaft indicate the pulley drive flange was not an interference fit or installed with Loctite locking compound.
4) The alloy spacer ring had been damaged around the circumference, probably during the recent installation process.
As the impellor blades tips have not been machined, this results in the seal installed height being increased were it will not hold pressure and leak.
Moving the seal away from the bearing casing reveals grease that should normally reside within the bearing.
During the dismantling process, the drive flange was found to be cracked and distorted as a result of not being pressed on square to the bearing spindle.
The impellor blades were subsequently machined to match the same angle on the new alloy spacer ring.
The pump was then re-assembled with all new components including a new bearing, alloy spacer ring, O-rings, seal and drive flange.
Before the new mechanical seal was installed, the crush height was checked against the manufacturers engineering drawings.
Final check is to pressure test the pump to 50psi - this provides piece of mind for all concerned!
Copyright © 2014 Lotus Marques
During the course of various telephone conversations it was established the pump belonged to a customer who is well known to us.
It appears this same customer purchased a water pump kit from the UK and did not receive comprehensive instructions on how to rebuild the pump successfully.
The photographs above are very useful when diagnosing why the freshly rebuilt pump has failed and allowed water to exit the weep hole.
Carefully examining the impellor, seal and bearing assembly reveals the following -
1) The brand new impellor blade tips have not been machined correctly when first manufactured.
2) Insufficient crush on the seal has allowed hot water to escape and enter the bearing where it has flushed out large amounts of grease.
3) Rust deposits on the bearing shaft indicate the pulley drive flange was not an interference fit or installed with Loctite locking compound.
4) The alloy spacer ring had been damaged around the circumference, probably during the recent installation process.
As the impellor blades tips have not been machined, this results in the seal installed height being increased were it will not hold pressure and leak.
Moving the seal away from the bearing casing reveals grease that should normally reside within the bearing.
During the dismantling process, the drive flange was found to be cracked and distorted as a result of not being pressed on square to the bearing spindle.
The impellor blades were subsequently machined to match the same angle on the new alloy spacer ring.
The pump was then re-assembled with all new components including a new bearing, alloy spacer ring, O-rings, seal and drive flange.
Before the new mechanical seal was installed, the crush height was checked against the manufacturers engineering drawings.
Final check is to pressure test the pump to 50psi - this provides piece of mind for all concerned!
Copyright © 2014 Lotus Marques